Sinusoidal fetal heart rate patterns in severe Rh disease.

Four patients with severe Rh isoimmunization are presented in whom sinusoidal fetal heart rate patterns were recorded. In 2 cases in which the pattern was seen intermittently in the postintrauterine transfusion period, the perinatal outcome was good. In the 2 cases in which the pattern was seen spontaneously and continuously, the outcome was poor, confirming the ominous and possibly agonal significance of the latter pattern.