Antepartum evaluation of the pre-ejection period of the fetal cardiac cycle.

The pre-ejection period (PEP) of the cardiac cycle was studied in 65 antepartum fetuses by means of a noninvasive technique which used simultaneous recordings of abdominal fetal electrocardiogram (FECG) and ultrasound fetal Doppler cardiogram (FDCG). Although most of the fetuses were products of high-risk pregnancies, 45 fetuses had uneventful perinatal courses. The PEP's from these fetuses demonstrated a significant positive relationship with gestational age (p is less than 0.01). Uterine contractions induced for antepartum stress testing of the fetus were founnd to prolong the PEP by approximately 9.1 per cent in five cases (four fetuses). The average PEP of antepartum fetuses between 38 and 40 weeks was shorter than that of intrapartum fetuses by approximately 9.5 per cent. Comparison between clinical outcome and the PEP's of the fetuses who were born within a week after the last determination of PEP revealed a strong correlation between prolonged PEP duration and abnormalities in the perinatal course.