Evidence-based surgical procedures to optimize caesarean outcomes: an overview of systematic reviews.

Background: Caesarean section (CS) is the most performed major surgery worldwide. Surgical techniques used for CS vary widely and there is no internationally accepted standardization. We conducted an overview of systematic reviews (SR) of randomized controlled trials (RCT) to summarize the evidence on surgical techniques or procedures related to CS. Methods: Searches were conducted from database inception to 31 January 2024 in Cochrane Database of Systematic Reviews, PubMed, EMBASE, Lilacs and CINAHL without date or language restrictions. AMSTAR 2 and GRADE were used to assess the methodological quality of the SRs and the certainty of evidence at outcome level, respectively. We classified each procedure-outcome pair into one of eight categories according to effect estimates and certainty of evidence. The overview was registered at PROSPERO (CRD 42023208306). Findings: The analysis included 38 SRs (16 Cochrane and 22 non-Cochrane) published between 2004-2024 involving 628 RCT with a total of 190,349 participants. Most reviews were of low or critically low quality (AMSTAR 2). The SRs presented 345 procedure-outcome comparisons (237 procedure versus procedure, 108 procedure versus no treatment/placebo). There was insufficient or inconclusive evidence for 256 comparisons, clear evidence of benefit for 40, possible benefit for 17, no difference of effect for 13, clear evidence of harm for 14, and possible harm for 5. We found no SRs for 7 pre-defined procedures. Skin cleansing with chlorhexidine, Joel-Cohen-based abdominal incision, uterine incision with blunt dissection and cephalad-caudal expansion, cord traction for placental extraction, manual cervical dilatation in pre-labour CS, changing gloves, chromic catgut suture for uterine closure, non-closure of the peritoneum, closure of subcutaneous tissue, and negative pressure wound therapy are procedures associated with benefits for relevant outcomes. Interpretation: Current evidence suggests that several CS surgical procedures improve outcomes but also reveals a lack of or inconclusive evidence for many commonly used procedures. There is an urgent need for evidence-based guidelines standardizing techniques for CS, and trials to fill existing knowledge gaps. Funding: UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), a cosponsored programme executed by the World Health Organization (WHO).