Haemodynamic Effects of Low Doses of Female Sex Steroids

Abstract

Summary: Haemodynamic changes were monitored serially in 3 groups of healthy young women taking (i) a combined oestrogen‐gestagen oral contraceptive containing a low dose of oestrogen, (ii) an oestrogen alone and (iii) a gestagen alone. Similar significant increases in plasma volume occurred in those women taking the combined preparation and in those taking the oestrogen. A small but significant decrease in forearm blood flow occurred in subjects taking the combined oral contraceptive. Cardiac output, blood pressure, heart rate and hand blood flow did not alter significantly in any of the 3 groups of subjects, while body weight increased in the subjects taking gestagen alone.It is concluded that the combined oestrogen‐gestagen oral contraceptives containing 50 μg. of oestrogen result in minimal haemodynamic side effects, and hence are safer than the older combined preparations containing a higher dose of oestrogen. The increase in plasma volume observed was due to oestrogen rather than gestagen. No additional information was obtained concerning the site of sex steroid action in the cardio‐vascular system.