Caesarean section and placental transfer of alcuronium

The placental transfer of alcuronium was studied in twelve patients undergoing elective or emergency caesarean section. Umbilical cord vein and maternal plasma was analysed for alcuronium at dose-delivery time intervals ranging from 5 to 10.5 minutes. The mean umbilical vein concentration of the relaxant was 0.41 +/- 0.18 (SD) microgram/ml, and the mean foetal/maternal concentration ratio was 0.26 +/- 0.11. A positive correlation between foetal and maternal concentrations of alcuronium was demonstrated. Although alcuronium appears to cross the placenta rapidly and in reasonably high concentration, no apparent adverse effects on the neonates was evident as judged by measurement of Apgar scores.