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Objective: To assess endothelial cell function throughout normal human pregnancy., Design: Longitudinal observational study., Population: Pregnant women attending antenatal clinics and female nursing staff., Methods: Flow mediated dilatation (FMD) was measured by high resolution ultrasound and used as a surrogate measure for endothelial cell function and measured in pregnant women and in non-pregnant female controls. Measurements were performed throughout normal pregnancies in each trimester., Results: Mean FMD was increased by 80% and 64% in the third trimester compared to the first and second trimesters, respectively, and by 92% compared to the mean FMD of the non-pregnant controls. The increased FMD in the third trimester was demonstrated to be statistically significant in comparison with all the above groups by two-sample t-tests (P < 0.01 for all comparisons)., Conclusion: Endothelial cell function, measured by ultrasound assessment of FMD, is enhanced in late normal human pregnancy.

One hundred and sixty-three haemodynamic studies were done serially in 23 normotensive and 25 mildly hypertensive women during pregnancy. With all subjects resting in the left lateral position, heart rate, cardiac output, stroke volume, left ventricular work index, total peripheral vascular resistance and haematocrit were all significantly higher while plasma volume per unit body weight was significantly lower in the hypertensive than in the normotensive pregnant women. It is postulated that this hyperkinetic circulatory state is due to hyperactivity of the sympathetic adrenergic component of the autonomic nervous system in hypertensive pregnancy.

Serial haemodynamic and systolic time interval measurements in 17 male transsexuals during high-dose oestrogen administration were compared with control values obtained after oestrogen withdrawal. During oestrogen treatment, cardiac output, stroke volume, plasma volume and total blood volume increased while total peripheral resistance, diastolic blood pressure and red cell mass decreased significantly. Changes in heart rate and systolic blood pressure were not significant. Despite a much higher dose of oestrogen, the haemodynamic changes observed in this study are similar in magnitude to those occurring in women taking oral contraceptives. Significant changes in systolic time intervals during oestrogen treatment were a shortened pre-ejection period (PEP) index, a prolonged left ventricular ejection time (LVET) index and a decreased PEP/LVET ratio indicating that left ventricular performance was augmented.