A case is reported where a sinusoidal fetal heart rate pattern was found in a fetus at 34 weeks. This pattern, at first isolated and later persistent for several hours, during a normal pregnancy became progressively transformed into a silent pattern. Cesarean delivery then performed resulted in the birth of an infant affected by a severe anemia due to a major feto-maternal transfusion and it died aged 36 h. The authors enquire into the significance of this pattern when found in apparently normal pregnancies, not involving rhesus iso-immunization, and they suggest a possible management when confronted with a sinusoidal fetal heart pattern.