Fetotoxic potential of general anaesthesia in relation to pregnancy.

Fifty-three infants with neural tube defects and 97 with other major congenital abnormalities have been reviewed. In only one case did the mother receive an anaesthetic before or during pregnancy and this anaesthetic is unlikely to have played any part in the outcome. The anaesthetic history was recorded for 471 mothers who booked consecutively for their confinements. Seventy-two women received 76 anaesthetics, 70 before the last menstrual period and six during pregnancy. The corrected annual incidence of anaesthesia was about 20% (14% related to fertility). There were no fetal abnormalities, but two miscarriages in the women anaesthetized during pregnancy. There was one abnormal baby delivered to a women anaesthetized more than 12 weeks before the last menstrual period.