Oral contraceptives and myocardial infarction.

Between January 1970 and December 1972 22 women aged between 31 and 45 years were admitted to the coronary care unit with acute myocardial infarction and six of these (27%) had been taking oral contraceptives. There were nine women aged 40 or less and five of them (55%) had been on oral contraceptives while three of the other four had been sterilized by tubal interruption.Both these figures of prevalence of oral contraceptive use are significantly greater than estimates for the general population of women of similar age. For those aged 30-44 years, current estimates suggest that it is between 8 and 11%.All the women in this study had risk factors recognized as being associated with the premature development of ischaemic heart disease, and the prevalence of these risk factors was similar in those taking oral contraceptives as in those not doing so. Oral contraceptives probably enhance the chance of developing myocardial infarction in women whose risk is increased for other reasons.