Blood pressure and heart rate in the ovine fetus: ontogenic changes and effects of fetal adrenalectomy

The role of fetal cortisol in cardiovascular maturation in late gestation in the chronically instrumented sheep fetus has been studied. The fetal arterial blood pressure (FABP) and fetal heart rate (FHR) of five animals have been recorded continuously from 120 days of gestation to spontaneous term labor. The peak times and amplitudes of cosinor analysis were then compared at 120-126, 127-133 and 134-140 days of gestation. Results showed an increase in FABP but a decrease in FHR which are maintained consistently from 120 to 140 days of gestation. The higher FABP is controlled by the fetal adrenal but do not prevent cortisol from sustaining a higher FABP.