Haematology of pregnancy

Abstract

Obstetric haematology has expanded as a specialism over the past 20 years in recognition of the growing understanding that pregnancy outcomes can be significantly impacted by haematological disease, and that pregnancy can trigger new diseases. Physiological changes that occur during pregnancy to meet the needs of the developing fetus can lead to complications in vulnerable women, including those with pre-existing haematological conditions. For example, the massive increase in uterine blood flow and vascular compliance necessary to maintain the blood supply to the developing fetus can lead to significant haemorrhage at the time of placental separation. Increasing hypercoagulability helps prevent this but raises the potential for systemic thromboembolic events. Despite increased understanding of these risks, haemorrhage and thrombosis remain leading causes of maternal death. The most common medical disorders in pregnancy are also haematological, being anaemia and thrombocytopenia, affecting around 25% and 10% of pregnant women, respectively. Fetal anaemia and thrombocytopenia may also occur, due to fetal-maternal alloimmunization. Obstetric haematology is a high-stakes area of practice that requires specialist knowledge and collaboration across disciplines.