Cardiovascular dynamics in women during the menstrual cycle and oral contraceptive therapy.

, , 567-570. Measurements of pulmonary blood flow and cardiac output have been made in 31 healthy women during the follicular and luteal phases of their menstrual cycle using nitrous oxide whole body plethysmography. The women were divided into three groups: 12 women were receiving oestrogen-progestogen contraceptive pills, 8 were receiving progestogen-only pills, and 11 were using either alternative methods of contraception or none at all. There was no significant difference in the values of cardiac index, pulmonary arterial distensibility, heart rate or systemic blood pressure during the two phases of the menstrual cycle in any of the three groups. When the three groups were compared the cardiac output showed the most significant difference, being greatest in the oestrogen-progestogen group, the progestogen-only group occupying an intermediate position. An increased cardiac output might play a part in the development of systemic hypertension in some women receiving oral contraceptives and could also add a risk to women with pre-existing heart disease.