Urinary incontinence developmental trajectories and risk predictors: a prospective study from pregnancy to 4 years after childbirth.

BACKGROUND: Urinary incontinence is a prevalent and bothersome health problem amongst women worldwide. Recognizing urinary incontinence trajectories and associated risk predictors are crucial for the prevention of urinary incontinence across the life course. Little was known about the developmental trajectories of urinary incontinence in adults. The study aims to identify the developmental trajectories of urinary incontinence from pregnancy to 4.5 years after childbirth and develop a dynamic nomogram based on the risk predictors of the incontinence trajectories. METHODS: This was a long-term prospective study. A total of 1243 pregnant women were enrolled in late pregnancy and followed up at 6 to 8 weeks postpartum, one year and 4.5 years postpartum. Group-based trajectory modeling was applied to identify unrecognized trajectories of urinary incontinence from pregnancy to 4.5 years after childbirth. Logistic regression analysis with a backward stepwise process was conducted for risk predictor selection. Decision curve analysis was applied to assess the net benefit of the nomogram. Bootstrapping procedure with 1000 resamples was performed for internal validity. RESULTS: A total of 1184 (95.3%) women who completed at least two follow-up assessments were included for trajectory analysis. Two distinct trajectories of urinary incontinence were identified with satisfactory model adequacy. Of the participants, 395 (33.4%) had persistently high risk of developing incontinence and 789 (66.6%) had low risk. Six risk predictors were associated with increased risk of developing high risk trajectory. Urinary incontinence before pregnancy was the strongest predictor (OR, 4.5; 95%CI, 3.0-6.5). A dynamic nomogram was developed by integrating the predictors, showing good predictive performance and clinical usability. CONCLUSIONS: One third of women were in persistently high risk group of urinary incontinence after childbirth. UI history before pregnancy, familial predisposition, vaginal birth, older age at first birth, greater pre-pregnancy BMI and living in rural areas were associated with increased risk of persistently high risk incontinence trajectory. Preventive efforts such as weight management before pregnancy and supervised pelvic floor muscle training could be made as early as possible.