The significance of sinusoidal fetal heart rate pattern during labor and its relation to fetal status and neonatal outcome.

Twenty-seven cases of sinusoidal fetal heart rate were studied. This group had a mean scalp pH of 7.288, significantly lower (p less than 0.005) than that of the control group. The mean one-minute Apgar score was 7.148, significantly lower (p less than 0.001) than the control group's mean score. Almost half (48,15%) of the fetuses had a one-minute Apgar score of 7 or less. Every fetus was viable. Amplitude of the pattern was found to correlate with neonatal depression, the larger the amplitude, the more profound the depression. Over 96% of the fetuses had cord-related deceleration patterns, and nearly 63% had obvious cord complications. It is postulated that sinusoidal patterns are an umbilical cord-related phenomenon, resulting from an alternating hypovolemia and hypervolemia. Clinicians are urged to scrutinize carefully any cases of this pattern, and perform an immediate fetal scalp blood pH determination. If the pH determination obtained is less than 7.25, the authors suggest intervention and operative delivery.