Analgesic efficacy and safety of transversus abdominis plane block in women undergoing cesarean delivery: An umbrella review of systematic reviews and meta-analyses.

Intrathecal morphine (ITM) remains the benchmark for post-cesarean analgesia but is frequently associated with opioid-related adverse effects. Regional analgesia techniques such as transversus abdominis plane block (TAPB) are increasingly used as an opioid-sparing alternative. Multiple systematic reviews and meta-analyses (SRMAs) have evaluated TAPB efficacy, yet findings remain fragmented, heterogeneous, and methodologically inconsistent. This umbrella review synthesizes and critically appraises the highest-level evidence on the analgesic efficacy and safety of TAPB after cesarean delivery (CD). A PROSPERO-registered umbrella review was conducted according to PRISMA 2020 and PRIOR guidelines. SRMAs of randomized controlled trials (RCTs) evaluating TAPB for post-cesarean analgesia were systematically searched across major databases until October 31, 2025. Methodological quality was assessed using AMSTAR-2, overlap quantified via corrected covered area (CCA), and pooled findings reanalyzed using the metaUmbrella platform. Evidence credibility was evaluated using Ioannidis' criteria and certainty using GRADE. Fourteen SRMAs encompassing 125 RCTs (60 unique) were included. Study overlap was moderate (CCA 8.33%). AMSTAR-2 ratings revealed variable quality: four high-quality, eight low-quality, and two critically low-quality reviews. Reanalysis demonstrated that TAPB provided small but statistically significant reductions in 24-hour pain at rest (SMD - 0.11), pain on movement (SMD - 0.12), and opioid consumption (SMD - 0.19). All achieved Class IV (weak) evidence with low GRADE certainty. No significant differences were observed in early (6-12-hour) pain or time-to-rescue analgesia. TAPB showed a favorable trend toward reduced postoperative nausea and vomiting, though with high heterogeneity. ITM offered modestly superior early analgesia, but differences were below minimal clinically important thresholds and accompanied by more opioid-related side effects. Despite extensive literature, the overall credibility and certainty of evidence supporting TAPB after CD remain weak due to heterogeneity, methodological limitations, and review redundancy. TAPB provides modest analgesic benefit and improved tolerability, supporting its role when neuraxial opioids are omitted, contraindicated, or declined. High-quality RCTs, standardized TAPB techniques, and core outcome sets are needed to refine clinical recommendations.