Investigating the association factors of acute postpartum pain: a cohort study

BACKGROUND: Labor pain intensity is known to predict persistent postpartum pain, whereas acute postpartum pain may interfere with maternal postpartum physical, mental, and emotional well-being. Nevertheless, there is little research studying the association between labor pain intensity and acute postpartum pain. This study investigated the associations between labor pain intensity and psychological factors with acute postpartum pain. METHODS: We included women with American Society of Anesthesiologists (ASA) physical status II, having ≥ 36 gestational weeks and a singleton pregnancy. We investigated the association between labor pain intensity (primary exposure) and high acute postpartum pain at 0 to 24 h after delivery (Numeric Rating Scale (NRS) ≥ 3 of 10; primary outcome). Pre-delivery questionnaires including Angle Labor Pain Questionnaire (A-LPQ), Pain Catastrophizing Scale (PCS), Fear Avoidance Components Scale (FACS) and State Trait Anxiety Inventory (STAI) were administered. Demographic, pain, obstetric and neonatal characteristics were also collected accordingly. RESULTS: Of the 880 women studied, 121 (13.8%) had high acute postpartum pain at 0 to 24 h after delivery. A-LPQ total, PCS, FACS and STAI scores were not significantly associated with acute postpartum pain. Greater A-LPQ subscale on birthing pain (adjusted odds ratio (aOR) 1.03, 95% CI 1.01–1.05, p = 0.0008), increased blood loss during delivery (for every 10ml change; aOR 1.01, 95% CI 1.00–1.03, p = 0.0148), presence of shoulder dystocia (aOR 10.06, 95% CI 2.28–44.36, p = 0.0023), and use of pethidine for labor analgesia (aOR 1.74, 95% CI 1.07–2.84, p = 0.0271) were independently associated with high acute postpartum pain. “Sometimes” having nausea during menstruation before current pregnancy (aOR 0.34, 95% CI 0.16–0.72, p = 0.0045) was found to be independently associated with reduced risk of high acute postpartum pain. CONCLUSIONS: Pre-delivery pain factor together with obstetric complications (shoulder dystocia, blood loss during delivery) were independently associated with high acute postpartum pain. TRIAL REGISTRATION: This study was registered on clinicaltrials.gov registry (NCT03167905) on 30/05/2017.