Fetal anemia and heart rate patterns

A retrospective survey was performed of the clinical records and cardiotocograms (CTG) of fetuses born in 1978 and 1979 at Helsinki University Central Hospital with hemoglobin concentration less than 170 g/liter in peripheral blood or umbilical artery. Eighty-three fetuses (0.7%) had thus defined anemia. Thirty-eight of them had late decelerations, 29 silent and nine sinusoidal fetal heart rate (FHR) patterns. Late decelerations and sinusoidal patterns were significantly more often associated with severe (hemoglobin concentration less than 80 g/liter) than with moderate anemia. The fetal outcome in terms of perinatal death and low APGAR scores after sinusoidal pattern was poorer than without this pattern, but the difference was not statistically significant. It is concluded that intermittent sinusoidal FHR pattern with late decelerations is suggestive of fetal anemia.