Antenatal investigation of human fetal systolic time intervals.

A noninvasive method for measuring the antenatal human fetal systolic time intervals with the use of the transabdominal fetal electrocardiogram and Doppler cardiogram is described. Unique interactive computer routines were developed for rapid and accurate determination of the pre-ejection period (PEP), ventricular ejection time (VET), PEP/VET ratio, and fetal heart rate (FHR). Thirty normal patients were monitored between 20 and 40 weeks of gestation. A regression analysis of the fetal systolic time intervals and FHR against gestational age was done. PEP and PEP/VET ratio were significantly correlated to the gestational age, while VET and FHR were not.