Central and peripheral haemodynamic changes in post-term fetuses: correlation with oligohydramnios and abnormal fetal heart rate pattern.
OBJECTIVE: To assess the hypothesis that the occurrence of oligohydramnios and abnormal fetal heart rate (FHR) pattern in post-term fetuses is associated with impaired fetal cardiac function. DESIGN: A cross sectional study was performed on post-term and term fetuses. Fetal tests included a computerised analysis of the FHR, a biophysical profile and Doppler studies of the abdominal aorta, umbilical artery, middle cerebral artery and the fetal heart. Pulsatility index (PI) was calculated from the abdominal aorta, umbilical and middle cerebral artery flow velocity waveforms. Peak velocity, velocity time integral (VTI), E:A ratio, and heart rate (HR) were calculated from the flow velocity waveforms obtained from the aortic and pulmonic outflow, and from the mitral and tricuspid valves. SETTING: Maternal fetal laboratory, Department of Obstetrics. SAMPLE: One hundred and twenty post-term and 42 term fetuses. RESULTS: Only the tricuspid E:A ratio was significantly higher (P