Background: Maternal predictors of folic acid (FA) supplementation use to reduce offspring risk of neural tube defects are well known, while paternal determinants for maternal FA use are less known. Such knowledge is important to increase women’s compliance to recommended periconceptional FA use. Methods: In a nation-wide study of 683,785 births registered in the Medical Birth Registry of Norway during 1999–2010, the associations between paternal characteristics (age, education, occupation, country of origin) and maternal FA use were estimated by relative risks (RR) with 95% confidence intervals (CI), using log- binomial regression. Results: Maternal FA use before and during pregnancy (adequate FA use) was found in 16% of the births. The association between paternal age and adequate FA use was inversely U-shaped; adjusted RRs for adequate FA use were 0.35 (95% CI 0.28–0.43) and 0.72 (95% CI 0.71–0.74) for paternal age < 20 and ≥ 40 years, respectively, comparing age 30–34 years. Compulsory education (1–9 years) among fathers was compared to tertiary education; the RR was 0.69 (95% CI 0.68–0.71) for adequate FA use. The lower risk of adequate FA use for paternal compulsory education was present in all categories of maternal education. Occupation classes other than “Higher professionals” were associated with decreased risk of adequate FA use, compared with the reference “Lower professionals”.RRfor adequate FA use was 0.58 (95% CI 0.56–0.60) comparing fathers from “Low/middle-income countries” with fathers born in Norway. Conclusion: Adequate FA use in the periconceptional period was lower when fathers were younger or older than 30–34 years, had shorter education, had manual or self-employed occupations, or originated from low/ middle-income countries. Partners may contribute to increase women’suse of periconceptional FA supplementation. Keywords: Pregnancy, Supplement use, Folic acid, Norway Background . Start of FA supplementation prior to conceiving is Folate is necessary in foetal development, and folic acid important in order to reduce the risk of NTDs because (FA) supplementation is widely acknowledged to reduce the neural tube closes between 21 and 28 days after the risk of neural tube defects (NTDs) [1–5]. FA is the conception . synthetic form of the B-vitamin folate, which is essential Randomized clinical trials and non-randomized in the synthesis of DNA, methylation, and DNA repair intervention trials have demonstrated that periconcep- tional FA use reduces the risk of NTDs [1–3]. Recent * Correspondence: firstname.lastname@example.org studies have reported that FA is associated with protec- Department of Global Public Health and Primary Care, University of Bergen, tion against other neurodevelopmental disorders and Kalfarveien 31, N-5018 Bergen, Norway some severe pregnancy complications [8–10]. The pro- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway tective effect of FA on NTDs has led health authorities Full list of author information is available at the end of the article © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Mortensen et al. BMC Pregnancy and Childbirth (2018) 18:188 Page 2 of 8 in several countries, including Norway, to recommend MBRN is a population-based registry containing women to take FA supplements before pregnancy and in information on all births in Norway since 1967 . The early pregnancy [11–13]. registry holds demographic information on the mother Many countries in Europe, including Norway, have and the father, the mother’s health before and during performed information campaigns to increase the use of pregnancy, including chronic diseases, information on in periconceptional FA supplementation among women vitro fertilization (IVF), complications during pregnancy planning pregnancy [14–16]. Presently there is no and delivery as well as information on the infant, includ- mandatory folic acid food fortification in Norway . ing birth defects and other perinatal problems. Midwives Official Norwegian guidelines from 1998, states that all and physicians attending the deliveries register the data. women planning their pregnancy should use 0.4 mg FA Since 1967, there has been mandatory reporting of all daily from 1 month before pregnancy and throughout live and stillbirths from the 16 gestational week to the first 2–3 months of pregnancy to reduce the risk of MBRN. NTDs . However, the proportion of preconception NR contains demographic information on all residents FA supplementation use in Norway is still too low  in Norway since 1960, including the date of birth, and by 2015 it was 33% . country of origin, and the dates of immigration, emigra- Previous studies have identified maternal factors tion, or death . NR assigns a unique personal identi- associated with inadequate FA in the periconceptional fication number to all individuals born or immigrated to period, such as low maternal age, shorter education, Norway, enabling accurate record linkages. single parenthood, unplanned pregnancy, lower parity, NAV was established in 2006 after governmental smoking, alcohol use, less physical activity, or originating reorganization of the Directorate of Labour in Norway from a foreign country [15, 16, 20–24]. (founded in 1945), and has registered information on Since couples tend to exhibit concordant health occupation, health status, and social benefits of all indi- behaviour’s for dietary intake, smoking, alcohol viduals with residence in Norway since 1992. The consumption, physical activity, and body mass index Norwegian occupational code system is based on the (BMI) [25–27], a woman’s partner may contribute to her International Standard Classification of Occupations use of periconceptional FA supplements. In fact, in an (ISCO), revised version from 1988 . early report from the Norwegian Mother and Child Since 1970, NUDB holds information on all individ- Cohort Study (MoBa), 2000–2003, counting 22,500 uals’ education history from primary school up to women, FA supplements were used more frequently doctoral studies in one database . The classification among women with partners with a higher education is based on the Norwegian Standard Classification of . However, the study did not assess other paternal Education. factors or combined paternal and maternal factors as to identify women with inadequate FA use. Maternal FA supplement use Taking advantage of the Medical Birth Registry of We constructed a binary variable for intake of FA sup- Norway that to our knowledge is the only national regis- plement use (0.4 mg/day) (regardless of concomitant try with information on periconceptional use of FA sup- multivitamin use) registered in the MBRN since Decem- plements , we updated parent information with data ber 1998 onwards; adequate FA use (recommended FA from national registries to investigate whether paternal supplementation before and during pregnancy), and in- factors (age, education, occupation, country of origin) adequate FA use (FA supplementation only before preg- was associated with mothers’ intake of recommended FA nancy, or only during pregnancy, or no record of FA in pregnancy. use). MBRN also registers multivitamin use, but our investi- gation focused on periconceptional FA use as such in- Methods take was according to official guidelines. Data-sources Maternal FA use before and/or during pregnancy was Paternal characteristics collected from the Medical Birth Registry of Norway We used the following paternal variables in our (MBRN) . Paternal and maternal demographic data analyses of adequate FA supplementation; paternal came from the National Registry (NR). Information on age (< 20, 20–24, 25–29, 30–34, 35–39, 40+ years); paternal and maternal occupation originated from the education (Compulsory (1–9 years), Intermediate (10– Norwegian Labour and Welfare Administration (NAV), 12 years), Tertiary (13–19 years)); occupation accord- and we retrieved paternal and maternal educational data ing to the class scheme of Erikson, Goldthorpe, and from the Norwegian National Education Database Portocarero (I Higher professionals, II Lower profes- (NUDB) . sionals, IIIa Higher routine, IIIb Lower routine, IV Mortensen et al. BMC Pregnancy and Childbirth (2018) 18:188 Page 3 of 8 Other self-employed workers, V Technicians, VI overall difference between the categories of paternal Skilled, VII Semiskilled and unskilled, VIIb Agricul- characteristics were calculated using likelihood ratio tural, Unclassified) (EGP) ; and country of origin tests. We evaluated and tested the potential effect modi- according to the classification by World Health fication of the association between paternal education Organization, Health statistics and information sys- and maternal FA use by stratification and likelihood ra- tems, Estimates for 2000–2012 (Norway, High income tio test. countries, Low/middle-income countries) . Covariates Results We used directed acyclic graphs (DAGs) and Our study included 683,785 births during 1999–2010. subject-matter knowledge to select a minimally sufficient Table 1 presents the characteristics of the parents. The adjustment set of variables that identify the uncon- median ages of the fathers and mothers at childbirth founded association of paternal characteristics on ad- were 33 and 30 years, respectively. For about 41% of the equate maternal FA supplementation use [35–37]. births, the mothers were primiparous, and about 2% of The potential confounders of the paternal characteris- the births were conceived after in vitro fertilization tics and maternal FA use relationship included year of (IVF). The majority of the births were of childbirth (continuous), paternal age (< 20, 20–24, 25– Norwegian-born parents (84% of the fathers and 83% of 29, 30–34, 35–39, 40+ years), education (Compulsory, the mothers). For about 34% of the births, the fathers Intermediate, Tertiary), or country of origin (Norway, had tertiary education, and for about 19% of the births, High-income countries, Low/middle-income countries). the fathers had compulsory education only. The paternal Furthermore, we included maternal age (< 20, 20–24, educational level varied by his country of origin. Fathers 25–29, 30–34, 35–39, 40+ years), maternal education originating from low/middle-income countries generally (Compulsory, Intermediate, Tertiary), and maternal had lower educational level compared to fathers origin- country of origin (Norway, High-income countries, Low/ ating from Norway and other high-income countries middle-income countries) as possible confounders of the (not shown). Occupation classified as “Lower profes- associations between paternal age, education, or country sionals,” accounted for 22% of all the births. For about of origin, and maternal adequate FA use. 14% of the births, the women smoked daily at the start Maternal smoking was not included in the final of pregnancy, about 3% smoked intermittently, and 67% models because smoking was not considered a con- did not smoke. Nearly 17% of the smoking data were founder of the association of paternal characteristics on missing. maternal FA supplementation use . For about 16% of all births in the study population, the mothers were assigned to the category adequate FA Study population supplementation users. However, during 1999 through During 1999–2010, 716,021 births were registered in 2010, the proportion of adequate FA supplementation MBRN. We excluded births (induced abortions) without use increased from 4% at the start of the study period information on FA or multivitamin supplementation use (1999) to 26% in 2010. (2519) and births without maternal identification num- Table 2 presents crude and adjusted RRs for ad- ber (4091). For multiple births, we included data for the equate maternal periconceptional FA use by paternal first birth and excluded 12,927 next born individuals. variables (determinants). Adjusted analyses showed an Among the remaining 696,484 births, we excluded inverse “U-shaped” relationship between paternal age 12,699 births without paternal identification number, and adequate maternal FA supplement use where the leaving 683,785 live births and stillbirths for analyses. smallest RRs were found for paternal age below 20 years (RR 0.35 (95% CI 0.28–0.43)), 20–24 years Statistical analysis (RR 0.68 (95% CI 0.66–0.71)), and 40 years and above Associations between paternal characteristics (age, edu- (RR 0.72 (95% CI 0.71–0.74)) compared to paternal cation, occupation, country of origin) and maternal FA age 30–34 years. Paternal compulsory education was use were estimated as relative risks (RRs) with 95% con- associated with reduced risk of adequate FA use (RR fidence intervals (CIs) by log-binomial regression, using 0.69 (95% CI 0.68–0.71)) compared to paternal ter- the log-link function in Stata version 15 . The 95% tiary education. All paternal occupation classes were CIs were based on robust variance estimation with the associated with reduced risk of adequate FA use ex- sandwich estimator to correct for the intra-individual cept for “I Higher professionals”,whencomparedto correlation in women with more than one pregnancy “II Lower professionals”, in particular “VII Semiskilled during the study period . Births with missing data on and unskilled” (RR 0.75 (95% CI 0.73–0.76)), and covariates were excluded from the analyses. P-values for “VIIb Agricultural” (RR 0.73 (95% CI 0.69–0.78)). Mortensen et al. BMC Pregnancy and Childbirth (2018) 18:188 Page 4 of 8 Table 1 Paternal and maternal characteristics in 683,785 births Table 1 Paternal and maternal characteristics in 683,785 births in Norway, 1999–2010 in Norway, 1999–2010 (Continued) Births Maternal chronic disease Fathers % Mothers % No 623,817 91.2 Number of births 683,785 100.0 683,785 100.0 Yes 59,968 8.8 Age Maternal smoking before pregnancy < 20 4401 0.6 15,464 2.3 Non-smoker 456,797 66.8 20–24 48,448 7.1 100,016 14.6 Intermittent 18,518 2.7 25–29 162,671 23.8 223,480 32.7 Daily 93,662 13.7 30–34 235,401 34.4 228,203 33.4 Missing data 114,808 16.8 35–39 151,540 22.2 99,727 14.6 Maternal folic acid use in pregnancy 40+ 81,324 11.9 16,895 2.5 No use 371,820 54.4 Education Only before 8930 1.3 Compulsory education (1–9 years) 130,953 19.2 125,479 18.4 Only during 192,169 28.1 Intermediate (10–12 years) 302,384 44.2 230,320 33.7 Before and during 110,866 16.2 Categorized according to the class scheme of Erikson, Goldthorpe and Tertiary education (13–19 years) 229,818 33.6 298,036 43.6 Portocarero (EGP)  Missing data 20,630 3.0 29,950 4.4 Categorized according to the classification by World Health Organization, Health statistics and information systems, Estimates for 2000–2012  Occupational class Asthma, hypertension, kidney disease, chronic urinary infection, rheumatoid I Higher professionals 86,635 12.7 50,650 7.4 arthritis, heart disease, epilepsy, diabetes mellitus (type I or II), and thyroid disease II Lower professionals 152,781 22.3 122,804 18.0 IIIa Higher routine 77,540 11.3 197,174 28.8 Mothers whose children’s father originated from low/ middle-income countries had also a reduced risk of ad- IIIb Lower routine 40,070 5.9 114,795 16.8 equate FA use (RR 0.58 (95% CI 0.56–0.60)) compared IV Other self-employed workers 358 0.1 119 0.0 to fathers originating from Norway. V Technicians 5550 0.8 1492 0.2 Table 3 presents crude and adjusted RRs with 95% CIs VI Skilled 108,755 15.9 15,961 2.3 of adequate FA use by maternal and paternal education. VII Semiskilled and unskilled 111,584 16.3 73,994 10.8 Adjusted analyses showed that adequate FA use was less VIIb Agricultural 7663 1.1 2720 0.4 likely in births were fathers had compulsory education, regardless of maternal education. The association of pa- Unclassified 52,824 7.7 51,264 7.5 ternal compulsory education and recommended FA use Missing data 40,025 5.9 52,812 7.7 was weakened by increasing level of maternal education. Country of origin However, even when the mother had tertiary education, Norway 574,602 84.0 567,241 83.0 the association of compulsory paternal education on ad- High income countries 33,487 4.9 30,920 4.5 equate maternal FA use was significant (RR 0.75 (95% CI Low/middle-income countries 75,497 11.0 85,597 12.5 0.73–0.77)), compared to fathers with tertiary education. Missing data 199 0.0 27 0.0 Discussion Marital status The present population-based study (683,785 births Unmarried 37,057 5.4 during 1999–2010) showed that recommended maternal Married/Partnership 634,283 92.8 FA use was low among fathers who were young or older Divorced 3417 0.5 at their children’s birth, had achieved shorter education, Missing data 9028 1.3 held a manually or self-employed occupation, or originated from low/middle-income countries. Even In vitro fertilization (IVF) among mothers who had achieved higher education, rec- No 669,024 97.8 ommended periconceptional maternal FA use was low Yes 14,761 2.2 among less educated fathers. Birth order Several studies have investigated the association be- 1 280,178 41.0 tween maternal socio-demographic, reproductive, and 2 244,532 35.8 medical characteristics and adherence to recommended intake of periconceptional FA. A common feature among ≥3 159,075 23.3 mothers is that young age, low educational level, low Mortensen et al. BMC Pregnancy and Childbirth (2018) 18:188 Page 5 of 8 Table 2 Relative risks (RRs) with 95% confidence intervals (95% CIs) of adequate maternal periconceptional folic acid supplement use (before and during pregnancy) by paternal characteristics, in 683,785 births, Norway, 1999–2010 ab Folic acid supplementation Unadjusted Adjusted for paternal factors Further adjusted for maternal ac use factors Characteristics Yes No RR* 95% CI RR* 95% CI RR* 95% CI Paternal age (years) < 20 86 4315 0.11 0.09–0.13 0.10 0.08–0.13 0.35 0.28–0.43 20–24 3325 45,123 0.37 0.36–0.39 0.37 0.36–0.38 0.68 0.66–0.71 25–29 22,886 139,785 0.76 0.75–0.78 0.77 0.76–0.79 0.94 0.93–0.96 30–34 43,348 192,053 1.00 Reference 1.00 Reference 1.00 Reference 35–39 28,488 123,052 1.02 1.01–1.03 0.97 0.96–0.99 0.90 0.89–0.91 40+ 12,733 68,591 0.85 0.83–0.87 0.80 0.78–0.81 0.72 0.71–0.74 Paternal education Compulsory (1–10 years) 11,694 119,259 0.40 0.39–0.40 0.52 0.51–0.53 0.69 0.68–0.71 Intermediate (11–13 years) 45,411 256,973 0.67 0.66–0.67 0.75 0.74–0.76 0.87 0.85–0.88 Tertiary (14–20 years) 51,894 177,924 1.00 Reference 1.00 Reference 1.00 Reference Missing data 1867 18,763 Paternal occupational class I Higher professionals 19,957 66,678 1.05 1.04–1.07 1.05 1.03–1.06 II Lower professionals 33,366 119,415 1.00 Reference 1.00 Reference IIIa Higher routine 12,292 65,248 0.73 0.71–0.74 0.89 0.88–0.91 IIIb Lower routine 5352 34,718 0.61 0.59–0.63 0.85 0.83–0.87 IV Other self-employed workers 60 298 0.77 0.61–0.97 0.83 0.65–1.05 V Technicians 836 4714 0.69 0.65–0.74 0.89 0.84–0.95 VI Skilled 15,174 93,581 0.64 0.63–0.65 0.84 0.83–0.86 VII Semiskilled and unskilled 11,643 99,941 0.48 0.47–0.49 0.75 0.73–0.76 VIIb Agricultural 908 6755 0.54 0.51–0.58 0.73 0.69–0.78 Unclassified 7575 45,249 0.66 0.64–0.67 0.96 0.94–0.99 Missing data 3703 36,322 Paternal country of origin Norway 99,339 475,263 1.00 Reference 1.00 Reference 1.00 Reference High income countries 6535 26,952 1.13 1.10–1.16 1.06 1.04–1.09 1.06 1.03–1.08 Low-middle-income countries 4975 70,522 0.38 0.37–0.39 0.35 0.34–0.36 0.58 0.56–0.60 Missing data 17 182 All RRs for adequate folic acid supplementation adjusted for year of childbirth (continuous) RRs by paternal age, no other adjustment for paternal factors; RRs by paternal education adjusted for paternal age (< 20, 20–24, 25–29, 30–34, 35–39, 40+), paternal country of origin (Norway, high-income countries, low/middle-income countries); RRs by paternal occupation adjusted for paternal age, fathers country of origin, fathers education (compulsory, intermediate, tertiary); and RR by paternal origin of country, no other adjustment for paternal factors RRs by paternal age, further adjusted for maternal age (< 20, 20–24, 25–29, 30–34, 35–39, 40+); RRs by paternal education, further adjusted for maternal education (compulsory, intermediate, tertiary); RRs by paternal occupation, no further adjustment for maternal factors; RRs by paternal country of origin adjusted for maternal country of origin (Norway, High-income countries, Low/middle-income countries) Categorized according to the class scheme of Erikson, Goldthorpe and Portocarero (EGP)  Categorized according to the classification by World Health Organization, Health statistics and information systems, Estimates for 2000–2012  *p-value for difference between categories of paternal characteristics was < 0.001 using likelihood ratio test socioeconomic status, unplanned pregnancy, higher par- In Denmark, a cross-sectional study consisting of ity, smoking, single marital status, and non-western 22,000 pregnant women (primiparious and multipar- birthplace is the most important determinants for inad- ous) showed that only 14% of the women used FA as equate FA supplementation use [20–23]. Furthermore, recommended and compliance was positively associ- maternal chronic diseases and IVF were positively asso- ated with being primiparous, older than 25 years and ciated with adequate periconceptional FA supplementa- non-smoker . Similarly, for about 16% of the tion use [22, 38]. births in our study, the mothers had followed the Mortensen et al. BMC Pregnancy and Childbirth (2018) 18:188 Page 6 of 8 Table 3 Relative risks (RRs) with 95% confidence intervals (95% CI) of adequate maternal periconceptional folic acid supplement use (before and during pregnancy) by combining maternal and paternal education in 683,785 pregnancies, Norway, 1999–2010 Adequate folic acid use Unadjusted Adjusted Maternal education Paternal education Yes No RR* 95% CI RR* 95% CI Compulsory education Compulsory education 2557 48,326 0.46 0.43–0.50 0.53 0.50–0.57 Intermediate education 4758 52,693 0.77 0.72–0.81 0.76 0.72–0.81 Tertiary education 1292 10,651 1.00 Reference 1.00 Reference Missing information 208 4994 Intermediate education Compulsory education 5079 43,708 0.60 0.57–0.62 0.66 0.64–0.68 Intermediate education 18,055 116,378 0.77 0.75–0.79 0.81 0.79–0.83 Tertiary education 7477 35,269 1.00 Reference 1.00 Reference Missing information 426 3928 Tertiary education Compulsory education 3805 17,985 0.70 0.67–0.72 0.75 0.73–0.77 Intermediate education 22,150 80,373 0.86 0.85–0.87 0.88 0.87–0.89 Tertiary education 42,541 126,896 1.00 Reference 1.00 Reference Missing information 747 3539 Missing data (maternal education) 28,179 1771 Adjusted for paternal age (< 20, 20–24, 25–29, 30–34, 35–39, 40+), year of childbirth (1999–2010 (continuous)), paternal country of origin (Norway, high income countries, low/middle income countries), stratified by maternal education *p values for interaction between maternal and paternal education were calculated by likelihood-ratio tests (unadjusted p value < 0.001; adjusted p value < 0.001) national guidelines of FA use in the study period and other European countries (Netherlands, Belgium, (1999–2010). Ireland and the United Kingdom) [23, 43–46]. These In Norway, a publication from the Norwegian Mother studies show that supplement use is less common and Child Cohort Study (MoBa), comprising 27% of the among most ethnic minority groups than among the births registered in MBRN during 2000–2003, showed comparison groups. We have similar findings in our similar results to ours . They found a positive associ- study, showing a lower risk of adequate maternal FA use ation between paternal education and recommended among fathers originating from low/middle-income periconceptional FA use. In pregnancies with fathers countries. having university or college education the adjusted rela- The strengths of our study included use of compre- tive risk (RR) of periconceptional maternal FA use was hensive data from population-based registries in Norway 1.4 (95% CI 1.1–1.8) compared to pregnancies with fa- that assures generalizability of our results, and registra- thers with primary education. However, the association tion of individual-level information on periconceptional was weaker than for maternal education. When paternal FA intake for all births in Norway since 1999 (except for tertiary education was compared to paternal compulsory terminated pregnancies). education (reference) in our analyses, we found a similar Our study had some limitations. Maternal FA intake result for adjusted RR of 1.45 (95% CI 1.42–1.48). could have been misclassified; in the beginning of the Couples who live together share the same environ- study period, FA users were underreported to the MBRN ment, social network, financial resources, and to some . Our results may therefore be somewhat weaker extent, the same health risk; beneficial or negative to than the true associations. Furthermore, we could not health outcomes depending on the health behaviour of adjust for pregnancy planning, maternal physical activity the spouses [25, 27]. Furthermore, a Dutch study of or maternal use of alcohol [16, 18, 20–24], as these po- 40,000 individuals aged 25–74 years showed that women tential confounders/covariates were not available in our seems more affected by their partner’s educational level dataset. However, a recent longitudinal study during than men are with regard to healthy behaviour . 2014 on men’s pregnancy planning comprising about In accordance with our findings, a cross-sectional 800 participants in Sweden, showed that 81% of the household survey conducted in Pakistan (comprising pregnancies were planned and the level of paternal edu- 6266 women), showed that maternal intake of iron and cation was positively associated with pregnancy planning FA supplements was positively associated with the edu- . Moreover, data from 22,500 mothers in the MoBa cational status of the mothers’ husband . study with deliveries recorded in 2000–2003 showed that The association of ethnic background and maternal 78% of the mothers had planned their pregnancy . periconceptional FA use have been studied in Norway However, MoBA is not entirely representative of the Mortensen et al. BMC Pregnancy and Childbirth (2018) 18:188 Page 7 of 8 total pregnant population in Norway, since the partici- Funding The Norwegian Cancer Society, Western Norway Regional Health Authority, pants are somewhat better educated, slightly older at de- project number 911629 to Dr. Nina Øyen, and the University of Bergen livery, and with a lower percentage of smokers than the supported this study. The study sponsors had no role in the design, analysis, overall pregnant population. interpretation of data, or writing of this manuscript. Information about fathers was not available in 12,699 Availability of data and materials births (2% of all births in the study population) and were Principal investigator, prof. Nina Øyen, sought and obtained all permissions excluded from the study population. They represent to access data from the Medical Birth Registry of Norway (MBRN), the National Registry (NR), the Norwegian Labour and Welfare Administration, births with fathers unreported by the pregnant woman and the Norwegian National Education Database (NUDB). The datasets or fathers without identification number from the NR. analysed during the current study are not freely available due to national Among the excluded births (missing father information), regulations. 10% of the mothers had adequate periconceptional FA Authors’ contributions supplementation (16% in the study population) with an JHM conceived the study, performed all analyses, and led the writing. NØ RR of 0.63 (95% CI 0.60–0.66) for adequate maternal FA and TB conceived the study and participated in manuscript preparation and writing. RMN participated in the analyses and writing. TF participated in the use comparing births with unregisterd fathers with statistical analyses. ST participated in manuscript preparation. All authors births having registered fathers. helped to conceptualize ideas, interpret findings, and review drafts of the Adjusting for maternal confounders (maternal age, manuscript. All authors read and approved the final manuscript. No conflicts of interest are declared. education, or country of origin) in our analysis reduced the strength of the associations between paternal deter- Ethics approval and consent to participate minants (age, education or country of origin) and ad- The study was approved by the Regional Committee for Medical and Health Research Ethics of Western Norway (REK ref. number 2010/3310). equate maternal periconceptional FA use. This suggest that paternal factors are important, but targeting mater- Competing interests nal demographic and socioeconomic conditions and The authors declare that they have no competing interests. other factors related to low use is still important. How- ever, our findings have implications for public health Publisher’sNote Springer Nature remains neutral with regard to jurisdictional claims in practice. Recent research on men’s birth intentions has published maps and institutional affiliations. shown that 63% of pregnancies were intended (wanted) by the father . Further, our study demonstrates the Author details Department of Global Public Health and Primary Care, University of Bergen, importance of the partner’s impact on maternal repro- Kalfarveien 31, N-5018 Bergen, Norway. Department of Obstetrics and ductive health and family planning through shared 3 Gynecology, Haukeland University Hospital, Bergen, Norway. Center for decision-making. Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway. Department of Health and Social Sciences, Western Norway University of Applied Sciences, Bergen, Norway. Cancer Registry of Conclusions Norway, Oslo, Norway. In conclusion, our study supports the importance of fa- Received: 4 February 2017 Accepted: 15 May 2018 ther’s prenatal role in their children’s health. In order to improve maternal periconceptional FA supplementation References use, information and knowledge about the importance of 1. MRC. Prevention of neural tube defects: results of the Medical Research FA’s preventive potential needs to be directed to both Council vitamin study. MRC vitamin study research group. Lancet. 1991; men and women. Furthermore, our findings show that 338(8760):131–7. 2. Czeizel AE, Dudas I. Prevention of the first occurrence of neural-tube defects women having partners originating from low/middle-in- by periconceptional vitamin supplementation. 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BMC Pregnancy and Childbirth – Springer Journals
Published: May 30, 2018
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