Anaesthesia for Caesarean section and neonatal acid‐base status: a meta‐analysis*

Abstract

Spinal anaesthesia is generally preferred for Caesarean section. Its superiority for the baby is often assumed. Umbilical artery acid‐base status provides a valid index of fetal welfare. Twenty‐seven studies reporting neonatal acid‐base data with different types of anaesthesia were used to compare umbilical artery or vein pH and base deficit, using random‐effect meta‐analysis. Cord pH was significantly lower with spinal than with both general (difference: −0.015; 95% CI −0.029 to −0.001; 13 studies, 1272 subjects) and epidural anaesthesia (difference −0.013; 95% CI −0.024 to −0.002; 11 studies, 828 subjects). Larger doses of ephedrine contributed to the latter effect (p = 0.023). Sixteen studies reported a base deficit, which was significantly higher for spinal than for general (difference 1.109; 95% CI 0.434–1.784 mEq.l⁻¹; seven studies, 695 subject) and epidural anaesthesia (difference 0.910; 95% CI 0.222–1.598 mEq.l⁻¹; seven studies, 497 subjects). Spinal anaesthesia cannot be considered safer than epidural or general anaesthesia for the fetus.