Introduction
Pregnancy involves many biochemical and physiological changes that influence the function of every organ system. In the liver, subtle changes in function are seen as a result of increasing circulating volume and venous changes. This is reflected by changes in the normal range for liver enzymes in pregnancy, compared to the non-pregnant population (Table 1).
The presence of mildly deranged liver function tests in pregnancy is common, seen in 3% of deliveries in one prospective study.4 Severe liver dysfunction is much rarer; at a major tertiary centre in London, only 54 cases of pregnancy-related liver failure were seen in an 11-year period.5
Severe liver disease in pregnancy was previously associated with high maternal mortality rates (up to 92% in acute fatty liver of pregnancy) but this has now fallen with advances in diagnosis, earlier identification and the development of new strategies for the management of hepatic disorders, including liver transplantation.5
It can be challenging to distinguish those conditions that have developed as a consequence of pregnancy from those that were present but not identified before pregnancy or those unrelated to pregnancy that have developed during the course of gestation.