Sinusoidal fetal heart rate pattern and severe fetal anemia.

This report describes a case of a sinusoidal fetal heart rate (FHR) pattern encountered in a fetus at 34 weeks' gestation during antepartum fetal stress testing because of maternal hypertension. Delivery of the fetus was accomplished, and the newborn was found to be severely anemic and hypotensive due to a massive fetomaternal transfusion. Some pathophysiologic mechanisms are suggested, and the clinical significance of this finding is discussed.