Urinary incontinence in nulliparous women before and during pregnancy: prevalence, incidence, type, and risk factors

While many women report urinary incontinence (UI) during pregnancy, associations with pre-pregnancy urinary leakage remain under-explained.

We performed a multi-strand prospective cohort study with 860 nulliparous women recruited during pregnancy.

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/m² (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/m² (AOR 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.

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.