Is general anaesthesia for caesarean section associated with postpartum haemorrhage? Systematic review and meta-analysis

Background Postpartum haemorrhage (PPH) remains a leading cause of maternal morbidity and mortality. The odds for PPH were about eight times higher following general anaesthesia compared with neuraxial anaesthesia in a recent retrospective study. We aimed to conduct a systematic review and meta-analysis of the effect of type of anaesthesia (general vs. neuraxial) on estimated blood loss and transfusion requirements after caesarean section. Methods A systematic literature search was performed. The quality of eligible reports was assessed using the Oxford Quality Scale. Data were subjected to meta-analysis using the random effects model. Results The search identified 18 articles including 12,330 parturients. Meta-analysis of randomised controlled trials (RCTs) found a significant difference in blood loss, favouring neuraxial anaesthesia (spinal and epidural) when comparing with general anaesthesia {weighted mean difference -106.11 ml [95% confidence interval (CI) -209.80, -2.42 ml], P = 0.04}. In further analyses, we found a significant difference after epidural compared with general anaesthesia but not after spinal compared with general anaesthesia. Based on RCTs, there was no significantly increased risk of blood transfusions with general anaesthesia. Analysis of non-randomised studies found a significantly higher transfusion requirement after general anaesthesia (risk ratio 5.06, 95% CI 2.47-10.36, P < 0.00001). The incidence of hypotension and the amount of fluid given were higher in the neuraxial anaesthesia groups. Conclusion General anaesthesia is associated with a higher blood loss than neuraxial anaesthesia. However, based on high-quality studies, the need for blood transfusion was not greater. The higher blood loss with general anaesthesia is therefore of uncertain clinical relevance.