Outcomes and outcome measures utilised in randomised controlled trials of postoperative caesarean delivery pain: a scoping review.

Background: Inadequately treated postoperative pain following caesarean delivery can delay recovery and the ability to care for a newborn. Effectiveness studies of interventions to treat postoperative caesarean delivery pain measure different outcomes, limiting data pooling for meta-analysis. We performed a comprehensive review of existing outcomes with the aim of recommending core outcomes for future research.

Methods: A scoping review to identify all outcomes reported in randomised controlled trials (RCTs) and clinical trial registries of interventions to treat or prevent postoperative caesarean delivery pain, with postoperative pain as a primary outcome measure. We searched PubMed, Web of Science, CINAHL, LILACS, Embase, CDSR and CRCT for studies from May 2016 to 2021. Outcomes were extracted and frequencies tabulated.

Results: Ninety RCTs and 11 trial registries were included. In total, 392 outcomes (375 inpatient and 17 outpatient) were identified and categorised. The most reported outcome domain was analgesia (n = 242/375, 64.5%), reported in 96% of inpatient studies, with analgesic consumption accounting for 108/375, 28.8% of analgesia outcomes. The second most common domain was pain intensity (n = 120/375, 32%), reported in 97% of inpatient studies, using the visual analogue scale (68/120, 59%) and the numerical reporting scale (37/120, 25%). Maternal and neonatal adverse effects accounted for 65/375 (17.3%) and 19/375 (5.1%) of inpatient outcomes, respectively.

Conclusions: Outcomes reported in RCTs for postoperative caesarean delivery pain vary widely. The results of this review suggest that standardisation is needed to promote research efficiency and aid future meta-analyses to identify optimal postoperative caesarean delivery pain management.