Incidence of chronic pelvic pain after childbirth and its causal association with C-section.

Abstract: This study aimed to report the incidence of chronic pelvic pain in women 12 to 24 months postpartum, to identify the independently associated factors, and to conduct a causal inference with C-section as the exposure. This was a cross-sectional study nested within 2 distinct prospective cohorts from 2 Brazilian cities. Chronic pelvic pain was the dependent variable. Independent variables were collected. Fisher exact test or Pearson χ2 test and t test or Wilcoxon rank-sum test were performed as appropriate, with P-values adjusted. Data were assumed to be missing at random, and multivariate imputation by chained equations was performed. Sensitivity analysis was conducted using complete cases. Multicollinearity was assessed by computing the variance inflation factor. Binomial logistic regression was used to obtain an interpretable model. Odds ratios and 95% confidence intervals were used as measurements. A directed acyclic graph was used for causal inference. A total of 2160 women were included. The incidence of chronic pelvic pain was 12.7%. C-sections doubled the odds of developing chronic pelvic pain (CPP). Additional factors associated with increased odds included city of birth, feelings of discrimination, severe symptoms of anxiety, dissatisfaction with the care received during childbirth, and mental suffering. Women who underwent C-sections had a 6.1% higher incidence of CPP compared to those who did not undergo the procedure. The incidence of CPP postpartum is high, and there is a potential causal effect of C-sections. City of birth, discrimination, anxiety, dissatisfaction with the care, and mental suffering were also associated with an increased odds.