Impact of prepregnancy body mass index on pregnancy outcomes, incidence of urinary incontinence and quality of life during pregnancy - An observational cohort study

BACKGROUND: To evaluate the effects of prepregnancy body mass index (BMI) on pregnancy outcomes, prevalence of urinary incontinence, and quality of life. METHODS: The observational cohort included 2210 pregnant women who were divided into 4 groups according to their prepregnancy BMI: underweight (<18.5), normal weight (18.5–24.9), overweight (25–29.9), and obese (≥30). Data were analyzed for pregnancy outcomes, prevalence of urinary incontinence during pregnancy, scores of the Short Form 12 health survey (SF-12) and changes in sexual function. RESULTS: Compared with normal weight, overweight and obesity were associated with advanced maternal age, low education level, multiparity, preterm delivery, cesarean section, gestational weight gain above the Institute of Medicine (IOM) guidelines, preeclampsia, gestational diabetes, macrosomia and large fetal head circumference. After adjusting for confounding factors, women with overweight and obesity were more likely to have adverse maternal outcomes (gestational weight gain above the IOM guidelines, preeclampsia and gestational diabetes) and fetal outcomes (large fetal head circumference and macrosomia) compared to normal weight women. Overweight and obese women (BMI ≥ 25) were more likely to have urinary incontinence than normal weight and underweight women. There were no significant differences in SF-12 scores among the 4 BMI groups, but more than 90% of pregnant women had reduced or no sexual activities regardless of BMI. CONCLUSIONS: Maternal prepregnancy overweight and obesity are associated with greater risks of preeclampsia, gestational diabetes, macrosomia and urinary incontinence. Health care providers should inform women to start their pregnancy at a BMI in the normal weight category.