Pattern of Congenital Anomalies in Newborn: A 4-Year Surveillance of Newborns Delivered in a Tertiary Healthcare Facility in the South-East Nigeria

Pattern of Congenital Anomalies in Newborn: A 4-Year Surveillance of Newborns Delivered in a... Abstract Congenital abnormalities are important causes of morbidity and mortality in children and significantly add to the burdens on healthcare in developing countries. Unfortunately, there remains a paucity of information on congenital birth defects in most developing countries. This is a 4-year prospective study that assessed the patterns and predictors of congenital anomalies among newborns at the Enugu State University Teaching Hospital, Nigeria. In total, 5830 deliveries were recorded, of which 38 had congenital anomalies, giving an incidence rate of 6.5/1000 live births. Fifty-two newborns were enrolled as nested controls. Factors significantly associated with congenital anomalies were low birth weight (p = 0.009), low socio-economic class (p = 0.011), lower maternal educational attainment (p = 0.009), parity of ≥ 5 (p = 0.002), febrile illness (p = 0.001) and the use of local concoction in index pregnancy (p = 0.009). More than half of the anomalies reported involved the musculoskeletal system. Occurrence of congenital anomalies may be prevented by curtailing risk factors identified in this study. congenital anomalies, newborn, incidence, pattern, Enugu INTRODUCTION Congenital malformations also referred to as birth defects are anomalies that occur in utero and are usually detected at birth [1]. These malformations can be structural or functional and can occur in isolation, in association, or as part of a syndrome. Congenital abnormalities are important cause of long-term morbidity, disability and mortality in children. They, most of the time, limit the newborns’ ability to adapt to extra-uterine life and may significantly reduce their quality of life. The impairments and handicaps that result from congenital malformations usually pose serious burdens on the health, social and financial well-being of the child, his/her family and the healthcare system. According to a 5-year mortality report released by the World Health Organization in 2005, >300 000 newborns die within the first month of life because of complications associated with congenital malformations [1]. A 23-year retrospective study done in south-south Nigeria estimated the prevalence of congenital anomalies in newborns to be 0.35% [2]. Although the exact cause of congenital malformations is usually unknown in about 50% of cases [3], it is however widely believed that most birth defects can be prevented by simple measures such as vaccination, folic acid supplementation, infection prevention and avoidance of certain indulgences like smoking, alcohol and use of certain drugs during pre-pregnancy and gestational periods [1]. In 2010, the World Health Organization in collaboration with other international organizations through the resolution on birth defects of the Sixty-third World Health Assembly recommended the promotion of primary prevention and improvement of the health of children with congenital anomalies. To achieve this, they proposed developing expertise on preventive strategies, developing and strengthening registration and surveillance systems and strengthening research and studies on aetiologies and diagnosis of congenital anomalies [1]. Despite these recommendations, there is a paucity of information on congenital birth defect in Nigeria and perhaps most developing countries because of little or no surveillance activities in this area. This 4-year passive surveillance study examined the pattern of congenital anomalies seen among newborns delivered in the Enugu State University Teaching Hospital (ESUTH). Secondarily, it also sought to explore maternal socio-demographic factors associated with the development of these anomalies in newborns. It is believed that the findings of this study will contribute to the body of knowledge on this subject and further strengthen practices that encourage prevention of birth defects and its associated medico-social consequences in children. METHODOLOGY Study area and site This was a prospective study carried out between the labour ward and the neonatal intensive care unit (NICU) of ESUTH, Parklane. The site is located within Enugu, the capital city of Enugu State, south-east Nigeria. ESUTH is a tertiary health institution that offers specialized medical services and serves as a referral centre to Private, General, Mission Hospitals and other delivery homes within Enugu and neighbouring States. The NICU offers 24-h services to newly delivered babies for observation and sick babies born within and outside the hospital. It is located in close proximity to the labour ward, which has an average of 144 deliveries per month. The special neonatal unit is manned by consultant neonatologists and resident doctors who are specialists in Paediatrics with further sub-specialist training in neonatology. Newborn participation and enrolment The study was carried out over a period of 4-year (January 2013–January 2017). Newborn babies of consenting mothers delivered in ESUTH that had congenital anomalies were consecutively enrolled and followed up with daily reviews till discharge or death. For every newborn with congenital anomalies enrolled, at least one newborn delivered around the same time matched as close as possible for anthropometric parameters was also enrolled. All anomalies encountered in enrolled newborns after delivery were documented. Other information collected included gestational age at delivery, anthropometric measurements as well as important obstetrics history. Some of these included maternal socio-demographic parameters, febrile illness during pregnancy, use of unprescribed medications and/or local concoction and pre-pregnant use of folic acid. The diagnosis of congenital malformations was based on clinical examination and laboratory and radiological investigations where appropriate. For the sake of this study, these diagnoses were made by a neonatologist who was not involved in this study. A second neonatologist was also brought in to confirm or refute the diagnosis in all cases. Data entry and analysis The above measures were documented at presentation in the relevant sections of the questionnaire and subsequently transferred into a Microsoft Excel Sheet. Distribution of the measures of outcome and predictor variables was analysed and recorded in percentages. Enrolees with significant missing information were excluded from the data analysis. The chi-square was used to assess variables significantly associated with congenital malformations in newborn. Data were analysed using IBM® SPSS version 18.0 (SPSS Inc, Chicago, IL). Statistical significance was set at p < 0.05. Ethical consideration Ethical clearance was obtained from the ESUTH Ethics Committee. Before recruitment of each subject, informed consent was obtained from every mother–newborn pair. Participation in the study was entirely voluntary, and no financial inducement whatsoever was involved. Participants were informed that voluntary withdrawal at any stage of interaction was guaranteed for them without any adverse effect to the mother or their baby. All information was handled with strict confidentiality. RESULT Characteristics of study respondents The surveillance for congenital abnormalities in newborn delivered at the ESUTH was carried out during a 4-year period. During this period, 5830 babies were delivered in the labour ward of the ESUTH giving an average of 122 births per month. Thirty-eight (∼0.7%) of these babies were born with one or more congenital anomalies giving an in-hospital incidence of rate of 6.5 per 1000 live births. Table 1 shows a summary of the characteristics of mothers and newborns enrolled for this study. In all, 90 newborns were enrolled with a male–female ratio of 1:4. Thirty-eight (48%) were born with one or more congenital malformation, while the remaining 52 (58%) had none. In total, 77% of the enrolled newborns were term deliveries and the remaining 23% were preterm (i.e. deliveries before 37 completed weeks of gestation). In total, 71% were born with a birth weight of ≥2.5 kg, while the rest were <2.5 kg at birth. In total, 11 of the 90 enrolled newborns died before discharge from the hospital and all were babies with congenital malformation. Majority (85%) of the mothers surveyed were <35 years old and 93% had parity of ≤ 4 at conception for the index baby. About two-thirds (63%) of the 90 respondents had post-secondary school education with the other 32 and 5% completing secondary and primary education, respectively. Table 1. Maternal and newborn parameters associated with occurrence of congenital deformity Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Notes: Bold values of p are statistically significant. a Fischer’s exact test used in estimation where applicable. Table 1. Maternal and newborn parameters associated with occurrence of congenital deformity Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Notes: Bold values of p are statistically significant. a Fischer’s exact test used in estimation where applicable. Predictors of congenital malformation in newborns Table 1 shows a cross-tabulation of maternal and newborn parameters considered in this study. Of parameters analysed only birth weight, socio-economic class, maternal educational attainment, parity, febrile illness with or without rash and use of local concoction in index pregnancy were significantly associated with congenital malformations in newborns. In total, 68% of newborns with birth weight <2.5 kg compared with 35% of newborns with birth weight ≥2.5 kg had congenital malformation (p = 0.009). Mothers in the low socio-economic class had 60% of the babies with congenital malformation compared with 39 and 20% for mother in the middle and high socio-economic class (p = 0.011). Similarly, it was noted that only 29% of mothers with post-secondary school education had a congenitally malformed baby compared with those with lower educational attainment (54% secondary education vs. 100% primary education or less; p = 0.009). Additionally, 37% of mothers with ≤4 children at the time of conception compared with 100% of mothers with ≥5 children at conception had congenitally malformed babies (p = 0.002). Furthermore, it was seen that 57% of mothers that had febrile illnesses and 68% that used local concoction during the index pregnancy compared with 21% without febrile illness and 35% of mother that did not use local concoction had babies with congenital anomalies (p = 0.001 and p = 0.009, respectively). Finally, mothers ≥35 years had more babies with congenital malformation (54%) than mothers that were ≤34 years (39%). This however did not attain statistical significance (p = 0.304). More babies with congenital anomalies (87%) than those without such anomalies (33%) had perinatal asphyxia (p = 0.001), and significantly, more babies with congenital anomalies died while in the NICU compared with babies without congenital anomalies (p = 0.000). Systems and organs involved in congenital malformations encountered in newborns Table 2 shows congenital malformation encountered in surveyed newborns occurred in isolation, in association or as known syndromes. A total of 133 clinically or radiological diagnosed anomalies were documented in the 38 newborns with congenital malformations. Seventeen (45%) of these newborns had anomalies that occurred in syndromic patterns, while the other 21 (55%) newborns had anomalies that occurred in isolations and/or associations that affected one or more systems. The syndromes encountered include Down syndrome, 8 (47%); Turner syndrome, 2 (12%); and congenital heart defects, 3 (17%). Others were Edward syndrome, 1 (6%); Potter’s syndrome, 1 (6%); osteogenesis imperfect, 1 (6%); and Smith–Lemli–Opitz, 1 (6%). The musculoskeletal system was the most affected with slightly >50% of deformities associated with this system. Twenty-two (16.5%) of abnormalities involved the digestive system, while the central nervous system (10.5%), the urogenital (8.0%) and integumentary system (8.3%) were approximately equally affected. Surprisingly, the cardiovascular system was the least involved system (6.7%) but was present in close to half of the newborns (45.5%) with congenital abnormalities that died after birth. Table 2 Deformitiesa encountered in newborns with congenital malformation Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 a Deformities encountered in newborns occurred either individually, in association or in syndromic pattern. Table 2 Deformitiesa encountered in newborns with congenital malformation Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 a Deformities encountered in newborns occurred either individually, in association or in syndromic pattern. DISCUSSION The overall incidence rate of congenital malformations in this study was 6.5 per 1000 live births. Though the incidence of congenital malformation in Nigeria has not been properly documented because of a lack of proper record-keeping [4], studies in this regard have revealed a wide variation in rates ranging between 2.2 per 1000 live births and 15.8 per 1000 live births in different zones of the country [5–8]. It is pertinent to note that these figures may be grossly underestimated because low autopsy rates and hospital-based data are limitations that influence accurate assessment of the magnitude of the problem in Nigeria [8]. The high rate of 15.8 per 100 live births was obtained from a study done in Lagos, south-west of Nigeria, and has been attributed to the multiethnic and industrial nature of Lagos suggesting genetic and environmental risk factors for the increased rate in the area [8]. In contrast to this, Rivers State, south-south Nigeria, an area also plagued by environmental pollution, recorded a low rate of 2.2 per 1000 births. There is need for more research into the association between congenital anomalies and environmental pollution in our environment in view of other risk factors such as smoking, alcohol, lack of adequate vaccination and folic acid supplementation, etc. This study demonstrated a strong association between increased parity and congenital malformations similar to findings in other studies [6, 8–10]. This is in contrast to a study that demonstrated more congenital malformations in primiparous mothers [11]. The difference may be explained by the fact that the effect of parity varies between different malformations [12]. For instance, the risk for polydactyly and syndactyly is higher than at low parity, whilst the opposite is true for conditions like hypospadias and omphalocele [12]. Mothers >35 years had more babies with congenital malformations than those <35 years. Although this was not statistically significant, it still reflects the well-known effect of advancing age on the incidence of congenital abnormalities [13]. For this reason, females who are >35 years of age need to be examined more carefully, as the risk of giving birth to a foetus with congenital malformations is greater [14]. It still remains unknown why advanced maternal age is an independent risk factor for foetal death. However, it has been suggested that the increasing age of mothers is associated with an increase in chromosomal meiotic errors [14]. Musculoskeletal abnormalities were observed to occur more frequently than other abnormalities in this study. This is in keeping with the findings of Christianson et al [15]. who noted higher musculoskeletal abnormalities than neural tube defect among black population. However, it is contrast to the findings of other local studies, which reported more digestive and central nervous system abnormalities [4, 6–8]. This difference may be because of the fact that musculoskeletal abnormalities may be perceived as being less severe with an increased likelihood of obtaining medical care, while paucity of diagnostic facilities and cost of surgical care may discourage presentation of the more severe digestive and central nervous system abnormalities. Although the cost of care for congenital abnormalities is expensive and unaffordable in developing countries like Nigeria, most birth defects can be prevented by simple measures such as vaccination, folic acid supplementation, infection prevention and avoidance of certain indulgences like smoking, alcohol and use of certain drugs during pre-pregnancy and gestational periods [1]. Effective implementation of these strategies may reduce mortality from congenital malformations, which are a significant cause of perinatal mortality. CONCLUSION This study reported a 6.5 per 1000 live birth incidence of congenital anomalies. The musculoskeletal system was most commonly affected. In decreasing order, the other systems involved were the digestive (16.5%), the central nervous (10.5%), the urogenital (8.0%), the integumentary (8.3%) and the cardiovascular (6.7%) systems. Among the significant associations identified with congenital malformations were birth weight, maternal socio-economic class, maternal educational attainment, parity, febrile illness and the use of local concoction in an index pregnancy. It was also found that babies with congenital anomalies have a higher tendency to either die in hospital or develop perinatal asphyxia compared with those without such anomalies. LIMITATIONS This study was conducted in resource-limited settings; hence, carrying out chromosomal studies to confirm diagnosis was not feasible. Also, some of the information provided by the respondents may have been affected by recall or intentional lie bias, especially for mothers whose babies had congenital anomalies and may not be psychologically disposed to grant interviews. FUNDING This work was completely sponsored by equal financial contributions from all authors. REFERENCES 1 World Health Organization fact sheet on congenital abnormalities . Available from http://www.who.int/mediacentre/factsheets/fs370/en/ and updated 2016 . 2 Ekanem TB , Okon DE , Akpantah AO , et al. Prevalence of congenital malformations in Cross River and Akwa Ibom states of Nigeria from 1980–2003 . Congenit Anom 2008 ; 48 : 167 – 70 . Google Scholar CrossRef Search ADS 3 Stevenson RE. The genetic basis of human anomalies. In: Stevenson RE , Hall JG , Goodman RM (eds). Human Malformations and Related Anomalies . Vol. 1 . New York, NY : Oxford University Press , 1993 , 115 . 4 Onankpa BO , Adamu A. Pattern and outcome of gross congenital malformations at birth amongst newborns admitted to a tertiary hospital in northern Nigeria . Niger J Paediatr 2014 ; 41 : 337 – 40 . Google Scholar CrossRef Search ADS 5 Ekanem TB , Bassey IE , Mesembe OE , et al. Incidence of congenital malformation in 2 major hospitals in Rivers state of Nigeria from 1990 to 2003/Incidence des malformations congenitales dans deux grands hopitaux de l'Etat de Rivers (Nigeria) de 1990 a 2003 . East Mediterr Health J 2011 ; 17 : 701 . Google Scholar CrossRef Search ADS PubMed 6 Onyearugha CN , Onyire BN. Congenital malformations as seen in a secondary healthcare institution in Southeast Nigeria . J Med Invest Pract 2014 ; 9 : 59 . 7 Mukhtar-Yola M , Ibrahim M , Belonwu R , et al. The prevalence and perinatal outcome of obvious congenital malformations among inborn babies at Aminu Kano Teaching Hospital, Kano . Niger J Paediatr 2005 ; 32 : 47 – 51 . 8 Iroha EO , Egri-Okwaji MT , Odum CU , et al. Perinatal outcome of obvious congenital malformation as seen at the Lagos University Teaching Hospital, Nigeria . Niger J Paediatr 2001 ; 28 : 73 – 7 . 9 Ambe JP , Madziga AG , Akpede GO , et al. Pattern and outcome of congenital malformations in newborn babies in a Nigerian teaching hospital . West Afr J Med 2010 ; 29 : 24 – 9 . Google Scholar PubMed 10 Jehangir W , Ali F , Jahangir T , et al. Prevalence of gross congenital malformations at birth in the neonates in a tertiary care hospital . APMC 2009 ; 3 : 47 – 50 . 11 Shawky RM , Elsedfy HH , Abolouz SK , et al. Prevalence of congenital malformations in a thousand consecutive Egyptian liveborn . Egypt J Med Hum Genet 2001 ; 2 : 43 – 53 . 12 Källén B. Epidemiology of Human Congenital Malformations . Cham, Heidelberg; New York, NY; Dodrecht; London : Springer , 2014 . Google Scholar CrossRef Search ADS 13 Nazer HJ , Cifuentes OL , Aguila RA , et al. The association between maternal age and congenital malformations . Rev Med Chil 2007 ; 135 : 1463 – 9 . Google Scholar PubMed 14 Khan A , Zuhaid M , Fayaz M , et al. Frequency of congenital anomalies in newborns and its relation to maternal health in a Tertiary Care Hospital in Peshawar, Pakistan . Int J Med Stud 2015 ; 3 : 19 – 23 . 15 Christianson AL , Howson CP , Modell B. March of Dimes: Global Report on Birth Defects, the Hidden Toll of Dying and Disabled Children. White Plains, New York: March of Dimes Birth Defects Foundation, 2006. © The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Tropical Pediatrics Oxford University Press

Pattern of Congenital Anomalies in Newborn: A 4-Year Surveillance of Newborns Delivered in a Tertiary Healthcare Facility in the South-East Nigeria

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Abstract

Abstract Congenital abnormalities are important causes of morbidity and mortality in children and significantly add to the burdens on healthcare in developing countries. Unfortunately, there remains a paucity of information on congenital birth defects in most developing countries. This is a 4-year prospective study that assessed the patterns and predictors of congenital anomalies among newborns at the Enugu State University Teaching Hospital, Nigeria. In total, 5830 deliveries were recorded, of which 38 had congenital anomalies, giving an incidence rate of 6.5/1000 live births. Fifty-two newborns were enrolled as nested controls. Factors significantly associated with congenital anomalies were low birth weight (p = 0.009), low socio-economic class (p = 0.011), lower maternal educational attainment (p = 0.009), parity of ≥ 5 (p = 0.002), febrile illness (p = 0.001) and the use of local concoction in index pregnancy (p = 0.009). More than half of the anomalies reported involved the musculoskeletal system. Occurrence of congenital anomalies may be prevented by curtailing risk factors identified in this study. congenital anomalies, newborn, incidence, pattern, Enugu INTRODUCTION Congenital malformations also referred to as birth defects are anomalies that occur in utero and are usually detected at birth [1]. These malformations can be structural or functional and can occur in isolation, in association, or as part of a syndrome. Congenital abnormalities are important cause of long-term morbidity, disability and mortality in children. They, most of the time, limit the newborns’ ability to adapt to extra-uterine life and may significantly reduce their quality of life. The impairments and handicaps that result from congenital malformations usually pose serious burdens on the health, social and financial well-being of the child, his/her family and the healthcare system. According to a 5-year mortality report released by the World Health Organization in 2005, >300 000 newborns die within the first month of life because of complications associated with congenital malformations [1]. A 23-year retrospective study done in south-south Nigeria estimated the prevalence of congenital anomalies in newborns to be 0.35% [2]. Although the exact cause of congenital malformations is usually unknown in about 50% of cases [3], it is however widely believed that most birth defects can be prevented by simple measures such as vaccination, folic acid supplementation, infection prevention and avoidance of certain indulgences like smoking, alcohol and use of certain drugs during pre-pregnancy and gestational periods [1]. In 2010, the World Health Organization in collaboration with other international organizations through the resolution on birth defects of the Sixty-third World Health Assembly recommended the promotion of primary prevention and improvement of the health of children with congenital anomalies. To achieve this, they proposed developing expertise on preventive strategies, developing and strengthening registration and surveillance systems and strengthening research and studies on aetiologies and diagnosis of congenital anomalies [1]. Despite these recommendations, there is a paucity of information on congenital birth defect in Nigeria and perhaps most developing countries because of little or no surveillance activities in this area. This 4-year passive surveillance study examined the pattern of congenital anomalies seen among newborns delivered in the Enugu State University Teaching Hospital (ESUTH). Secondarily, it also sought to explore maternal socio-demographic factors associated with the development of these anomalies in newborns. It is believed that the findings of this study will contribute to the body of knowledge on this subject and further strengthen practices that encourage prevention of birth defects and its associated medico-social consequences in children. METHODOLOGY Study area and site This was a prospective study carried out between the labour ward and the neonatal intensive care unit (NICU) of ESUTH, Parklane. The site is located within Enugu, the capital city of Enugu State, south-east Nigeria. ESUTH is a tertiary health institution that offers specialized medical services and serves as a referral centre to Private, General, Mission Hospitals and other delivery homes within Enugu and neighbouring States. The NICU offers 24-h services to newly delivered babies for observation and sick babies born within and outside the hospital. It is located in close proximity to the labour ward, which has an average of 144 deliveries per month. The special neonatal unit is manned by consultant neonatologists and resident doctors who are specialists in Paediatrics with further sub-specialist training in neonatology. Newborn participation and enrolment The study was carried out over a period of 4-year (January 2013–January 2017). Newborn babies of consenting mothers delivered in ESUTH that had congenital anomalies were consecutively enrolled and followed up with daily reviews till discharge or death. For every newborn with congenital anomalies enrolled, at least one newborn delivered around the same time matched as close as possible for anthropometric parameters was also enrolled. All anomalies encountered in enrolled newborns after delivery were documented. Other information collected included gestational age at delivery, anthropometric measurements as well as important obstetrics history. Some of these included maternal socio-demographic parameters, febrile illness during pregnancy, use of unprescribed medications and/or local concoction and pre-pregnant use of folic acid. The diagnosis of congenital malformations was based on clinical examination and laboratory and radiological investigations where appropriate. For the sake of this study, these diagnoses were made by a neonatologist who was not involved in this study. A second neonatologist was also brought in to confirm or refute the diagnosis in all cases. Data entry and analysis The above measures were documented at presentation in the relevant sections of the questionnaire and subsequently transferred into a Microsoft Excel Sheet. Distribution of the measures of outcome and predictor variables was analysed and recorded in percentages. Enrolees with significant missing information were excluded from the data analysis. The chi-square was used to assess variables significantly associated with congenital malformations in newborn. Data were analysed using IBM® SPSS version 18.0 (SPSS Inc, Chicago, IL). Statistical significance was set at p < 0.05. Ethical consideration Ethical clearance was obtained from the ESUTH Ethics Committee. Before recruitment of each subject, informed consent was obtained from every mother–newborn pair. Participation in the study was entirely voluntary, and no financial inducement whatsoever was involved. Participants were informed that voluntary withdrawal at any stage of interaction was guaranteed for them without any adverse effect to the mother or their baby. All information was handled with strict confidentiality. RESULT Characteristics of study respondents The surveillance for congenital abnormalities in newborn delivered at the ESUTH was carried out during a 4-year period. During this period, 5830 babies were delivered in the labour ward of the ESUTH giving an average of 122 births per month. Thirty-eight (∼0.7%) of these babies were born with one or more congenital anomalies giving an in-hospital incidence of rate of 6.5 per 1000 live births. Table 1 shows a summary of the characteristics of mothers and newborns enrolled for this study. In all, 90 newborns were enrolled with a male–female ratio of 1:4. Thirty-eight (48%) were born with one or more congenital malformation, while the remaining 52 (58%) had none. In total, 77% of the enrolled newborns were term deliveries and the remaining 23% were preterm (i.e. deliveries before 37 completed weeks of gestation). In total, 71% were born with a birth weight of ≥2.5 kg, while the rest were <2.5 kg at birth. In total, 11 of the 90 enrolled newborns died before discharge from the hospital and all were babies with congenital malformation. Majority (85%) of the mothers surveyed were <35 years old and 93% had parity of ≤ 4 at conception for the index baby. About two-thirds (63%) of the 90 respondents had post-secondary school education with the other 32 and 5% completing secondary and primary education, respectively. Table 1. Maternal and newborn parameters associated with occurrence of congenital deformity Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Notes: Bold values of p are statistically significant. a Fischer’s exact test used in estimation where applicable. Table 1. Maternal and newborn parameters associated with occurrence of congenital deformity Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Features Congenital malformation present χ2 Total Yes No pa Gestational age at delivery (n, 90)  Term 69 (77) 29 (48) 40 (58) 0.005  Preterm 21 (23) 9 (43) 12 (57) 0.946 Gender of newborn (n, 90)  Male 53 (59) 23 (43) 30 (57) 0.073  Female 37 (41) 15 (41) 22 (59) 0.787 Birth weight (n, 90)  ≥2.5 kg 71 (79) 25 (35) 46 (65) 6.776  <2.5 kg 19 (21) 13 (68) 6 (32) 0.009 Weight of newborn for gestational age (n, 88)  Adequate 77 (88) 31 (40) 46 (60) 0.107  Small 11 (12) 5 (45) 6 (55) 0.743 Maternal age at conception for index pregnancy (n, 88)  ≥35 years 13 (15) 7 (54) 6 (46) 1.056  <35 years 75 (85) 29 (39) 46 (61) 0.304 Socio-economic class (n, 88)  High 25 (28) 5 (20) 20 (80) 9.076  Middle 33 (38) 13 (39) 20 (61) 0.011  Low 30 (34) 18 (60) 12 (40) Mother educational attainment (n, 87)  Post-secondary 55 (63) 16 (29) 39 (71) 10.85  Completed secondary 28 (32) 15 (54) 13 (46) 0.004  Completed primary or less 4 (5) 4 (100) 0 (0) Parity of mother at conception (n, 88)  ≤4 82 (93) 30 (37) 52 (63) 9.301  ≥5 6 (7) 6 (100) 0 (0) 0.002 Antenatal care in index pregnancy (n, 90)  Yes 76 (84) 34 (5) 42 (55) 1.266  No 14 (16) 4 (29) 10 (71) 0.260 Febrile±rash illness in index pregnancy (n, 86)  Yes 44 (51) 25 (57) 19 (43) 11.26  No 42 (49) 9 (21) 33 (79) 0.001 Local concoction use in index pregnancy (n, 90)  Yes 19 (21) 13 (68) 6 (32) 6.776  No 71 (79) 25 (35) 46 (65) 0.009 Self-medication in index pregnancy (n, 83)  Yes 23 (28) 7 (30) 16 (70) 0.650  No 60 (72) 24 (40) 36 (60) 0.420 Pre-pregnancy folic acid use in index pregnancy (n, 87)  Yes 8 (9) 2 (25) 6 (75) 0.850  No 79 (91) 33 (42) 46 (58) 0.357 Asphyxia in newborn at birth (n, 90)  Yes 15 (17) 13 (87) 2 (13) 14.58  No 75 (83) 25 (33) 50 (67) 0.001 Outcome of newborn (n, 86)  Alive 75 (87) 23 (31) 52 (69) 19.29  Died 11 (13) 11 (100) 0 (0) 0.000 Notes: Bold values of p are statistically significant. a Fischer’s exact test used in estimation where applicable. Predictors of congenital malformation in newborns Table 1 shows a cross-tabulation of maternal and newborn parameters considered in this study. Of parameters analysed only birth weight, socio-economic class, maternal educational attainment, parity, febrile illness with or without rash and use of local concoction in index pregnancy were significantly associated with congenital malformations in newborns. In total, 68% of newborns with birth weight <2.5 kg compared with 35% of newborns with birth weight ≥2.5 kg had congenital malformation (p = 0.009). Mothers in the low socio-economic class had 60% of the babies with congenital malformation compared with 39 and 20% for mother in the middle and high socio-economic class (p = 0.011). Similarly, it was noted that only 29% of mothers with post-secondary school education had a congenitally malformed baby compared with those with lower educational attainment (54% secondary education vs. 100% primary education or less; p = 0.009). Additionally, 37% of mothers with ≤4 children at the time of conception compared with 100% of mothers with ≥5 children at conception had congenitally malformed babies (p = 0.002). Furthermore, it was seen that 57% of mothers that had febrile illnesses and 68% that used local concoction during the index pregnancy compared with 21% without febrile illness and 35% of mother that did not use local concoction had babies with congenital anomalies (p = 0.001 and p = 0.009, respectively). Finally, mothers ≥35 years had more babies with congenital malformation (54%) than mothers that were ≤34 years (39%). This however did not attain statistical significance (p = 0.304). More babies with congenital anomalies (87%) than those without such anomalies (33%) had perinatal asphyxia (p = 0.001), and significantly, more babies with congenital anomalies died while in the NICU compared with babies without congenital anomalies (p = 0.000). Systems and organs involved in congenital malformations encountered in newborns Table 2 shows congenital malformation encountered in surveyed newborns occurred in isolation, in association or as known syndromes. A total of 133 clinically or radiological diagnosed anomalies were documented in the 38 newborns with congenital malformations. Seventeen (45%) of these newborns had anomalies that occurred in syndromic patterns, while the other 21 (55%) newborns had anomalies that occurred in isolations and/or associations that affected one or more systems. The syndromes encountered include Down syndrome, 8 (47%); Turner syndrome, 2 (12%); and congenital heart defects, 3 (17%). Others were Edward syndrome, 1 (6%); Potter’s syndrome, 1 (6%); osteogenesis imperfect, 1 (6%); and Smith–Lemli–Opitz, 1 (6%). The musculoskeletal system was the most affected with slightly >50% of deformities associated with this system. Twenty-two (16.5%) of abnormalities involved the digestive system, while the central nervous system (10.5%), the urogenital (8.0%) and integumentary system (8.3%) were approximately equally affected. Surprisingly, the cardiovascular system was the least involved system (6.7%) but was present in close to half of the newborns (45.5%) with congenital abnormalities that died after birth. Table 2 Deformitiesa encountered in newborns with congenital malformation Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 a Deformities encountered in newborns occurred either individually, in association or in syndromic pattern. Table 2 Deformitiesa encountered in newborns with congenital malformation Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 Musculoskeletal system n, 67  Flat nasal bridge 6 (8.9) Right forearm shortening 1 (1.5)  Medial canthus hypertelorism 9 (13.4) Absent left forearm 1 (1.5)  Talipes deformities 8 (11.9) Absence of three medial fingers 2 (3.0)  Low set ears 9 (13.4) Syndactyly 1 (1.5)  Sanders feet 1 (1.5) Macrosomia 2 (3.0)  Toe misalignment 2 (3.0) Short neck 1 (1.5)  Receding chin 1 (1.5) Short webbed neck 5 (7.5)  Fixed flexing deformity of the wrist 2 (3.0) Left hemihypertrophy 1 (1.5)  Prominent philtrum 2 (3.0) Rocker bottom foot 1 (1.5)  High arched feet 1 (1.5) Anterior abdominal wall defect 1 (1.5)  Short lower limb 1 (1.5) Polydactyly 2 (3.0)  Malformed pinna 2 (3.0) Micro-opthalmia 2 (3.0)  Short sturdy fingers 2 (3.0) High arched palate 1 (1.5) Central nervous system n, 14  Microcephaly 3 (21.4) Sutural diastasis 1 (7.1)  Encephalocele 2 (14.3) Prominent occipitus 1 (7.1)  Meningocele 2 (14.3) Hydrocephalocele 1 (7.1)  Spinal bifidia occulta 2 (14.3) Macrocephaly 2 (14.3) Urogenital system n, 10  Hypospadia 1 (10.0) Clitomegaly 2 (20.0)  Micropenis 2 (20.0) Poorly developed scrotum 1 (10.0)  Bilateral undescended testis 1 (10.0) Cryptorchidism 1 (10.0)  Abnormal external genitalia 1 (10.0) Bilateral nephromegaly 1 (10.0) Digestive system n, 22  Tracheooesphageal fistula 2 (9.1) Imperforate anus 2 (9.1)  Duodenal atresia 2 (9.1) Macroglossia 2 (9.1)  Omphalocele 3 (13.6) Cleft lips 4 (18.2)  Micrognathia 7 (31.8) Cardiovascular system n, 9  Dextrocardia 1 (11.1) Patent ductus ateriosus 1 (11.1)  Ventricular septal defect 4 (44.4) Coarctation of the aorta 1(11.1)  Atrial septal defect 1 (11.1) Cyanotic congenital heart disease 1 (11.1) Integumentary system n, 11  Hypopigmentation of the face and neck 2 (18.2) Single palmar creases 3 (27.3)  Widely spaced nipples 1 (9.1) Redundant skin at back of neck 1 (9.1)  Slanting palpeberal fissure 4 (36.4) Total deformities encountered in newborns surveyed N=133 a Deformities encountered in newborns occurred either individually, in association or in syndromic pattern. DISCUSSION The overall incidence rate of congenital malformations in this study was 6.5 per 1000 live births. Though the incidence of congenital malformation in Nigeria has not been properly documented because of a lack of proper record-keeping [4], studies in this regard have revealed a wide variation in rates ranging between 2.2 per 1000 live births and 15.8 per 1000 live births in different zones of the country [5–8]. It is pertinent to note that these figures may be grossly underestimated because low autopsy rates and hospital-based data are limitations that influence accurate assessment of the magnitude of the problem in Nigeria [8]. The high rate of 15.8 per 100 live births was obtained from a study done in Lagos, south-west of Nigeria, and has been attributed to the multiethnic and industrial nature of Lagos suggesting genetic and environmental risk factors for the increased rate in the area [8]. In contrast to this, Rivers State, south-south Nigeria, an area also plagued by environmental pollution, recorded a low rate of 2.2 per 1000 births. There is need for more research into the association between congenital anomalies and environmental pollution in our environment in view of other risk factors such as smoking, alcohol, lack of adequate vaccination and folic acid supplementation, etc. This study demonstrated a strong association between increased parity and congenital malformations similar to findings in other studies [6, 8–10]. This is in contrast to a study that demonstrated more congenital malformations in primiparous mothers [11]. The difference may be explained by the fact that the effect of parity varies between different malformations [12]. For instance, the risk for polydactyly and syndactyly is higher than at low parity, whilst the opposite is true for conditions like hypospadias and omphalocele [12]. Mothers >35 years had more babies with congenital malformations than those <35 years. Although this was not statistically significant, it still reflects the well-known effect of advancing age on the incidence of congenital abnormalities [13]. For this reason, females who are >35 years of age need to be examined more carefully, as the risk of giving birth to a foetus with congenital malformations is greater [14]. It still remains unknown why advanced maternal age is an independent risk factor for foetal death. However, it has been suggested that the increasing age of mothers is associated with an increase in chromosomal meiotic errors [14]. Musculoskeletal abnormalities were observed to occur more frequently than other abnormalities in this study. This is in keeping with the findings of Christianson et al [15]. who noted higher musculoskeletal abnormalities than neural tube defect among black population. However, it is contrast to the findings of other local studies, which reported more digestive and central nervous system abnormalities [4, 6–8]. This difference may be because of the fact that musculoskeletal abnormalities may be perceived as being less severe with an increased likelihood of obtaining medical care, while paucity of diagnostic facilities and cost of surgical care may discourage presentation of the more severe digestive and central nervous system abnormalities. Although the cost of care for congenital abnormalities is expensive and unaffordable in developing countries like Nigeria, most birth defects can be prevented by simple measures such as vaccination, folic acid supplementation, infection prevention and avoidance of certain indulgences like smoking, alcohol and use of certain drugs during pre-pregnancy and gestational periods [1]. Effective implementation of these strategies may reduce mortality from congenital malformations, which are a significant cause of perinatal mortality. CONCLUSION This study reported a 6.5 per 1000 live birth incidence of congenital anomalies. The musculoskeletal system was most commonly affected. In decreasing order, the other systems involved were the digestive (16.5%), the central nervous (10.5%), the urogenital (8.0%), the integumentary (8.3%) and the cardiovascular (6.7%) systems. Among the significant associations identified with congenital malformations were birth weight, maternal socio-economic class, maternal educational attainment, parity, febrile illness and the use of local concoction in an index pregnancy. It was also found that babies with congenital anomalies have a higher tendency to either die in hospital or develop perinatal asphyxia compared with those without such anomalies. LIMITATIONS This study was conducted in resource-limited settings; hence, carrying out chromosomal studies to confirm diagnosis was not feasible. Also, some of the information provided by the respondents may have been affected by recall or intentional lie bias, especially for mothers whose babies had congenital anomalies and may not be psychologically disposed to grant interviews. FUNDING This work was completely sponsored by equal financial contributions from all authors. REFERENCES 1 World Health Organization fact sheet on congenital abnormalities . Available from http://www.who.int/mediacentre/factsheets/fs370/en/ and updated 2016 . 2 Ekanem TB , Okon DE , Akpantah AO , et al. Prevalence of congenital malformations in Cross River and Akwa Ibom states of Nigeria from 1980–2003 . Congenit Anom 2008 ; 48 : 167 – 70 . Google Scholar CrossRef Search ADS 3 Stevenson RE. The genetic basis of human anomalies. In: Stevenson RE , Hall JG , Goodman RM (eds). Human Malformations and Related Anomalies . Vol. 1 . New York, NY : Oxford University Press , 1993 , 115 . 4 Onankpa BO , Adamu A. Pattern and outcome of gross congenital malformations at birth amongst newborns admitted to a tertiary hospital in northern Nigeria . Niger J Paediatr 2014 ; 41 : 337 – 40 . Google Scholar CrossRef Search ADS 5 Ekanem TB , Bassey IE , Mesembe OE , et al. Incidence of congenital malformation in 2 major hospitals in Rivers state of Nigeria from 1990 to 2003/Incidence des malformations congenitales dans deux grands hopitaux de l'Etat de Rivers (Nigeria) de 1990 a 2003 . East Mediterr Health J 2011 ; 17 : 701 . Google Scholar CrossRef Search ADS PubMed 6 Onyearugha CN , Onyire BN. Congenital malformations as seen in a secondary healthcare institution in Southeast Nigeria . J Med Invest Pract 2014 ; 9 : 59 . 7 Mukhtar-Yola M , Ibrahim M , Belonwu R , et al. The prevalence and perinatal outcome of obvious congenital malformations among inborn babies at Aminu Kano Teaching Hospital, Kano . Niger J Paediatr 2005 ; 32 : 47 – 51 . 8 Iroha EO , Egri-Okwaji MT , Odum CU , et al. Perinatal outcome of obvious congenital malformation as seen at the Lagos University Teaching Hospital, Nigeria . Niger J Paediatr 2001 ; 28 : 73 – 7 . 9 Ambe JP , Madziga AG , Akpede GO , et al. Pattern and outcome of congenital malformations in newborn babies in a Nigerian teaching hospital . West Afr J Med 2010 ; 29 : 24 – 9 . Google Scholar PubMed 10 Jehangir W , Ali F , Jahangir T , et al. Prevalence of gross congenital malformations at birth in the neonates in a tertiary care hospital . APMC 2009 ; 3 : 47 – 50 . 11 Shawky RM , Elsedfy HH , Abolouz SK , et al. Prevalence of congenital malformations in a thousand consecutive Egyptian liveborn . Egypt J Med Hum Genet 2001 ; 2 : 43 – 53 . 12 Källén B. Epidemiology of Human Congenital Malformations . Cham, Heidelberg; New York, NY; Dodrecht; London : Springer , 2014 . Google Scholar CrossRef Search ADS 13 Nazer HJ , Cifuentes OL , Aguila RA , et al. The association between maternal age and congenital malformations . Rev Med Chil 2007 ; 135 : 1463 – 9 . Google Scholar PubMed 14 Khan A , Zuhaid M , Fayaz M , et al. Frequency of congenital anomalies in newborns and its relation to maternal health in a Tertiary Care Hospital in Peshawar, Pakistan . Int J Med Stud 2015 ; 3 : 19 – 23 . 15 Christianson AL , Howson CP , Modell B. March of Dimes: Global Report on Birth Defects, the Hidden Toll of Dying and Disabled Children. White Plains, New York: March of Dimes Birth Defects Foundation, 2006. © The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

Journal

Journal of Tropical PediatricsOxford University Press

Published: Aug 1, 2018

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