Abstract
The Oral Contraception Study of the Royal College of General Practitioners is a long-term, controlled, prospective survey which is now in its 14th year. The substantial data accumulated permits assessment of the effects of particular brands upon morbidity. We have shown that the progestogen content of the Pill is associated with the incidence of hypertension, benign breast disease and, more important, of total arterial disease. The data support the findings of other investigators who have shown that progestogens lower HDL-cholesterol levels and that low HDL-cholesterol increases the risk of arterial disease. The implications are that the progestogen content of an oral contraceptive and the relative potency of the estrogen and progestogen it contains must be considered carefully not only in terms of present clinical practice, but also in terms of the direction of new Pill formulation development.