Postpartum urinary retention: Absolute risk prediction model

Objectives: To evaluate the incidence and assess clinical factors that can predict the occurrence of postpartum urinary retention (PPUR). PPUR is a puerperal condition defined as the inability to void over 6 hours after birth or after catheter removal in case of cesarean section, requiring catheterization. Lack of prompt diagnosis of this condition may lead to severe sequelae, including infection, chronic voiding difficulties, and renal failure. Methods: This retrospective cohort study analyzed all deliveries from January 2011 to December 2017 in a single Italian university hospital. We used multivariate logistic regression to develop a predictive score for PPUR. Results: By multivariate logistic regression, our analysis shows as minor (odds ratio [OR] < 2) risk factors for PPUR: non-Caucasian ethnicity (OR = 1.46, CI = 1.05-2.03), nulliparity (OR = 1.47, CI = 1.01-2.14), body mass index (BMI) at the end of the pregnancy <30 kg/m2 (OR = 1.54, CI = 1.10-2.17). On the other hand, epidural analgesia (OR = 3.93, CI = 2.96-5.22), meconium-stained amniotic fluid (OR = 2.07, CI = 1.54-2.77), nonoperative vaginal birth vs cesarean section (OR = 6.25, CI = 2.16-18.13), vacuum extraction vs cesarean section (OR = 8.80, CI = 2.86-27.01), pushing stage ≥60 minutes (OR = 3.00,CI = 2.26-3.97), and perineal tear (OR = 2.87, CI = 1.86-4.43) proved to be major (OR > 2) risk factors for PPUR. Using our final model (area under curve = 0.84), we created a nomogram for PPUR absolute risk calculation. Specifically, a 116-point cutoff might be used to identify high-risk patients who deserve more intensive micturition monitoring. Conclusions: Our study identified non-Caucasian ethnicity, nulliparity, and a BMI <30 kg/m2 at the end of the pregnancy as minor and epidural analgesia, meconium-stained amniotic fluid, vaginal nonoperative birth, vacuum extraction, pushing stage ≥60 minutes, and perineal tear as major independent risk factors for PPUR.