FETAL HEART-RATE RESPONSES TO ANEMIA IN RH ISOIMMUNIZATION

On 52 occasions 24 Rh immunized women were monitored with a nonstress test (NST) prior to fetal blood sampling. Cardiotocographic characteristics were recorded for each NST. Fetal blood was analysed for hemoglobin and hematocrit. Fetal hemoglobin and hematocrit were positively correlated to long-term variability, acceleration amplitude and negatively correlated to deceleration amplitude (linear regression analysis; p < 0.05). Decelerations were almost without exception associated with low concentrations of hemoglobin and hematocrit. In fetuses of 32 weeks’ gestation or more, a loss of variability (≤ 5 bpm) was associated with severe anemia. Hemoglobin and hematocrit were significantly lower in the group with a pathological NST (n = 15) compared with the group with a normal NST (n = 37) (Mann-Whitney U test; p < 0.05). © 1990 Walter de Gruyter. All rights reserved.