ABSTRACT
In order to provide safe anaesthesia for the mother and foetus, it is essential to know about the physiological changes that characterise the three trimesters of pregnancy. Most physiological changes occur in response to the increased metabolic demands of the uterus, placenta and foetus. It is estimated that 1%–2% of pregnant women require incidental surgery during their pregnancy. Surgery is associated with a greater risk of abortion, growth restriction and low birth weight, although these problems probably result from the primary disease rather than the anaesthetic or surgery itself. Elective surgery should not be performed at all during pregnancy. The goals of providing anaesthesia to these patients: optimise and maintain normal maternal physiological function; optimise and maintain utero-placental blood flow and oxygen delivery; and avoid unwanted drug effects on the foetus. These also include avoid stimulating the myometrium; avoid awareness during general anaesthesia; and use regional anaesthesia if possible.
