Risk factors for postpartum urinary incontinence: The impact of early-onset and late-onset Gestational Diabetes Mellitus in a nested case-control study

Background: Gestational Diabetes Mellitus (GDM) and many other clinical variables have been associated with postpartum urinary incontinence (UI). However, the data are still restricted, and no study explored early- or late-onset GDM as a risk factor for this condition. We aimed to identify independent risk factors for postpartum UI, focusing on GDM and its early or late onset. Methods: A nested case control derived from the Diamater cohort study included 517 pregnant women who submitted to a planned C-section and followed by 6-18 months after delivery according to the timing of GDM diagnosis: early-onset GDM (before 20 weeks) and late-onset GDM(24-28 weeks) and the occurrence of UI. Results: Univariate analysis showed that the risk for 6-18 months postpartum UI was 49% higher in non-Caucasian ethnicity (1.49,1.02-2.18), 3,3 times higher in previous bariatric surgery [3.37,1.36-8.21], 39% higher in GDM women (1.39,1.01-1.93), and 5% higher for each BMI score in prepregnancy (1.05, 1.03-1.08) and at the end of pregnancy (1.05,1.02-1.08). Multivariate logistic regression analysis indicates that prepregnancy BMI was the only independent factor associated with the 6-18 months postpartum UI (adj 1.05, 95 %CI 1.02-1.08, P <.001). After stratifying, a second univariate and multivariate analysis were done according to the prepregnancy BMI cutoff score of 25. Thus, a significant association between GDM and postpartum UI in prepregnancy overweight women (RR: 1.91; 95 %CI 1.25-2.90, P =.003) and no association between GDM and 6-18 months postpartum UI in normal prepregnancy BMI (RR: 0.78, 95 %CI 0.39-1.54, P =.482) were found. After multivariate regression, the early-onset-GDM remained the unique independent adjusted risk factor for 6-18 months postpartum UI analysis (adjRR 2.15, 95 %CI 1.33-3.46, P =.002). Conclusion: After a planned C-section, we observed a 6-18 months postpartum UI higher occurrence after GDM, either in early-onset GDM or late-onset GDM. In addition, being overweight (BMI > 25) among women with early-onset GDM was associated with postpartum UI.