Influence of anaesthesia on the incidence of maternal morbidity, neonatal asphyxia, and perinatal mortality

Abstract

The incidence of maternal morbidity, neonatal asphyxia, and perinatal mortality associated with 169 forceps deliveries using pudendal nerve block, and with 198 forceps deliveries and 167 caesarean sections using three different types of general anaesthesia (induction with either cyclopropane or thiopentone, or induction and maintenance with ether, nitrous oxide and oxygen), in St. Thomas's Hospital and the General Lying-In Hospital between August, 1959, and December, 1960, were assessed and compared. The following observations were made. (1) The incidence of post-partum haemorrhage was lower with pudendal nerve block (5.3%) than with general anaesthesia (17%). (2) All three types of general anaesthesia were associated with the regurgitation of gastric contents. (3) The time between the induction of anaesthesia and the delivery of the infant with forceps was shorter with cyclopropane (13.8 minutes) and thiopentone (15.8 minutes) than with ether (26.7 minutes). (4) Male infants were more liable to be severely asphyxiated at birth than females. (5) The degree of neonatal asphyxia increased with the incidence of and need for operative intervention. (6) The incidence of severe neonatal asphyxia associated with forceps delivery was least when it was performed under pudendal block (11.3%), significantly greater with cyclopropane (33.2%) and thiopentone (26.9%), and greatest when ether (81.5%) was used. (7) No association could be found between the perinatal deaths and the type of anaesthetic used. It is concluded that local analgesia should be used whenever possible for forceps delivery because it is associated with less danger both for the mother and for the baby than general anaesthesia. Only skilled and experienced anaesthetists should be responsible for obstetric anaesthetics. The use of ether is associated with a high incidence of post-partum haemorrhage and severe neonatal asphyxia ; further, induction with ether is slow and unpleasant for the patient. For these reasons ether is not considered to be the general anaesthetic agent of choice for operative delivery. © 1963, British Medical Journal Publishing Group. All rights reserved.