Incidence, severity, and determinants of uterine contraction pain after vaginal delivery: a prospective observational study

Background: Postpartum uterine contraction pain has not been studied sufficiently. We aimed to assess the incidence, intensity, and risk factors for postpartum uterine contraction pain.

Methods: Women with singleton pregnancies who delivered vaginally were enrolled in this prospective, observational, single-institution study. We determined the numerical rating scale (NRS) score (0 to 10-point) for uterine contraction pain at 6, 12, 24, and 48 h after delivery. Generalized mixed modeling was used to identify the risk factors for significant postpartum uterine contraction pain (NRS score ≥3). We compared the incidence and severity of postpartum uterine contraction pain between nulliparous and multiparous women.

Results: Two hundred and sixty-five nulliparous and 139 multiparous women were included. Forty-seven percent (188/404; 95% confidence interval [CI] 41.7% to 51.4%) of women presented with significant uterine contraction pain within 48 h of delivery. The generalized mixed model showed that nulliparous women had a lower risk of significant postpartum uterine contraction pain compared with multiparous women (odds ratio [OR] 0.33, 95% CI 0.17 to 0.61; P<0.001). Women with a history of dysmenorrhea had higher risk of significant postpartum uterine contraction pain (OR 1.77, 95% CI 1.12 to 2.79; P=0.014). Both nulliparous and multiparous women reported more intense uterine contraction pain while breastfeeding (P<0.001).

Conclusions: Postpartum uterine contraction pain is common and severe in some women. Parity and history of dysmenorrhea are significant risk factors for significant postpartum uterine contraction pain.