Deleterious effect of an anaesthetic on cultured mammalian embryos

Abstract

THE teratogenic effect of certain tranquillisers on human and animal pregnancies has been known for many years^1–3. Anaesthetics and other central nervous system depressants may also be teratogenic when given during early pregnancy, possibly because of the inhibitory action of these agents on mitosis⁴. Anaesthetics can also activate unfertilised mouse eggs in vivo, inducing them to develop parthenogenetically^5,6. Chronic exposure to low levels of anaesthetics may result in a significant increase in spontaneous abortions and the birth of children with congenital abnormalities^7,8. Experiments with rodents⁹ which seemed to demonstrate that chronic exposure to anaesthetics could be teratogenic in early pregnancy have proved difficult to repeat¹⁰, so that doubt has now been cast on the validity of these earlier results. Attention has also been drawn to the possible risk to the human foetus of surgery carried out during pregnancy¹¹. In the experiments reported here we have demonstrated a direct, deleterious effect on early postimplantation rat embryos in culture of a single exposure to different doses of an anaesthetic.