The influence of infant birth weight on post partum stress incontinence in obese women.

One hundred ninety four women with a Body Mass Index (BMI) of at least 30 kg/m2 who were delivered vaginally between 01 10 93 and 30 09 95 at the obstetric department, Herning Central Hospital, were sent a postal questionnaire about stress incontinence. The response rate was 89.2%. In the heavy birth weight group (n = 4000 g or more) stress incontinence increased from 10.6% before pregnancy to 34.0% post partum. In the low birth weight group 6.9% suffered from stress incontinence before pregnancy increasing to 30.6% post partum. There was no difference in the reporting of mixed or urge incontinence between the two groups.