Myocardial Infarction

Cardiovascular Effects

The first report about a case of pulmonary embolism as adverse effect of contraception occurred in 1961 ⁽¹⁾.

Myocardial Infarction

In the last years, the incidence of myocardial infarction(MI) was estimated of 2 to5 fold for hormonal contraceptive (HC)-users compared with nonusers ^{( 2,3)}.

The risk results dose-related, and increased also for women using low-dose pill.

Coagulation factors, especially factors VII and fibrinogen, have been established as important cardiovascular risk factors in men. Some studies have shown the levels of factors VII and fibrinogen to be elevated in HC users.

These procoagulant alterations are also observed in women receiving estrogen substitution, but unlike HC users, such women appear to be protected by age-related increases in the level of antitrombin III ^(4,5).

Smoking is an important influence-factor on the fibrinogen level, which probably explains part of the increased risk of MI among HC users.
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Both, smoking and hypertension substantially increase the risk among HC users and some data suggest an increased risk among women with diabetes, hypercholesterolaemia or a history of pre-eclampsia or hypertension-pregnancy related.

The role of the different types of progestagens used in HCs is still controversial ^(6,7,8).

Clinical trials on myocardial infarction have found inconsistent results, possibly because of differences in the prevalence of risk factors, particularly smoking and elevated blood pressure, in the populations studied.

In the absence of a history of smoking and other conventional risk factors, current users of modern COCs probably do not have an increased risk of myocardial infarction. Neither are former users at risk ⁽⁹⁾.

Evidence for important differences in the risk of myocardial infarction between formulations is weak and contradictory.

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However, a study carried out on 217 women with a first myocardial infarction before the age of 50 years, and 763 healthy control women showed that the risk is substantially elevated among women with various inherited clotting factor defects ⁽¹⁰⁾.

The overall odds ratio for myocardial infarction, in the presence of a coagulation defect is 1.1.

The combination of a prothrombotic mutation and current smoking, increases the risk of myocardial infarction 12-fold compared with non-smokers, without a coagulation defect.
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