Limitations of middle cerebral artery peak systolic velocity in the detection of severe anaemia: A case report

Doppler examination of the fetal middle cerebral artery (MCA) is considered highly reliable in detecting severe fetal anaemia. We present a case of a mother with severe pre-eclampsia at 32 weeks' gestation and non-immune fetal hydrops without obvious cause. Since the MCA peak systolic velocity (PSV) was normal, severe anaemia was not considered as a possible cause, but after delivery the infant was found to be severely anaemic and died. Histological examination of the placenta revealed multiple extensive haemorrhages (subchorionic, intraparenchymal and intravillous), and autopsy indicated that the most likely cause of death was severe anaemia and hypoxia due to multiple and extensive placental haemorrhages, which had developed over the course of several days. We postulate that the MCA PSV failed to indicate severe anaemia because of the combination of subacute anaemia with severe profound hypoxia due to placental insufficiency.