Urinary incontinence in nulliparous women
before and during pregnancy: prevalence, incidence,
type, and risk factors
Received: 22 January 2017 / Accepted: 4 January 2018 /Published online: 23 January 2018
The International Urogynecological Association 2018
Introduction While many women report urinary incontinence (UI) during pregnancy, associations with pre-pregnancy urinary
leakage remain under-explained.
Methods We performed a multi-strand prospective cohort study with 860 nulliparous women recruited during pregnancy.
Results Prevalence of any urinary leakage was 34.8% before and 38.7% during pregnancy. Prevalence of UI, leaking urine at
least once per month, was 7.2% and 17.7% respectively. Mixed urinary incontinence (MUI) was reported by 59.7% of women
before and 58.8% during pregnancy, stress urinary incontinence (SUI) by 22.6% and 37.2%, and urge urinary incontinence (UUI)
by 17.7% and 4.0%, respectively. SUI accounted for half (50.0%), MUI for less than half (44.2%), and UUI for 5.8% of new-
onset UI in pregnancy. Pre-pregnancy UI was significantly associated with childhood enuresis [adjusted odds ratio (AOR) 2.9,
95% confidence interval (CI) 1.5–5.6, p = 0.001) and a body mass index (BMI) ≥30 kg/m
(AOR 4.2, 95% CI 1.9–9.4, p <0.001).
Women aged ≥35 years (AOR 2.8, 95% CI 1.4–5.9, p = 0.005), women whose pre-pregnancy BMI was 25–29.99 kg/m
2.0, 95% CI 1.2–3.5, p = 0.01), and women who leaked urine less than once per month (AOR 2.6, 95% CI 1.6–4.1, p <0.005)
were significantly more likely to report new-onset UI in pregnancy.
Conclusion Considerable proportions of nulliparous women leak urine before and during pregnancy, and most ignore symptoms.
Healthcare professionals have several opportunities for promoting continence in all pregnant women, particularly in women with
identifiable risk factors. If enquiry about UI, and offering advice on effective preventative and curative treatments, became
routine in clinical practice, it is likely that some of these women could become or stay continent.
Keywords Childhood enuresis
Prospective cohort study
The reported prevalence of pre-pregnancy urinary inconti-
nence (UI), all types combined, in nulliparous women varies
considerably and is 10.8% , 15.4% , or 39.0% de-
pending on the definition of UI used. Brown et al.’sstudy
illustrates these variations well; in their study, 41.1% of 1507
nulliparous women leaked some amount of urine pre-
pregnancy; 30.3% leaked less than once per month (occasion-
al leakage) and 10.8% monthly or more (defined as UI) . Of
the 10.8% of women who reported UI, 4.1% reported stress
urinary incontinence (SUI), 3.3% urge urinary incontinence
(UUI), and 3.5% mixed urinary incontinence (MUI). Of the
15.4% of nulliparous women reporting UI in Wesnes et al.’s
study , 8.7% reported SUI, 3.9% UUI, and 2.8% MUI.
Eliasson et al.  reported prevalence of any pre-pregnancy
* Deirdre Daly
School of Nursing and Midwifery, Trinity College Dublin, 24
D’Olier Street, Dublin DO2 T283., Ireland
Northern Ireland Methodology Hub, Centre for Public Health,
School of Medicine, Dentistry and Biomedical Sciences, Queen’s
University Belfast, Belfast BT12 6BJ., Northern Ireland
Institute of Health and Care Sciences, Sahlgrenska Academy,
University of Gothenburg, Gothenburg, Sweden
International Urogynecology Journal (2018) 29:353–362