Fetal anaemia

Fetal anaemia is a relatively rare occurrence, but it carries a risk of significant fetal morbidity and mortality. The most common causes of fetal anaemia are haemolytic disease of fetus and newborn and parvovirus B19 infection. The only diagnostic test for fetal anaemia is fetal blood sampling, but this is an invasive test with associated risk of miscarriage, preterm membrane rupture or intrauterine fetal death. Therefore it is only performed if there is a strong suspicion of fetal anamia based on the patient's history and ultrasound findings of raised peak systolic velocity in middle cerebral artery and/or fetal hydrops. The treatment for fetal anaemia is symptomatic rather than curative in most of the cases. In severely anaemic fetuses intrauterine blood transfusion is undertaken which corrects the anaemia but does not deal with the underlying cause. The aim of this intervention is to reach the gestation when the delivery is safer.