MECHANISMS OF HYPERCOAGULABILITY PROMOTED BY ORAL COMBINED CONTRACEPTIVES

Background: Hormonal contraceptive pills are the most used reversible method for familiarplanning in Brazil. The combined pill, with synthetic analogs of estrogen and progestin, isemployed by 25% of Brazilian female population. Its use provokes an increase of bloodpressure levels, takes patient to a hipercoagulability state and predisposes her tothromboembolic events. Purposes: We aimed to describe mechanisms of hypercoagulabilitypromoted by oral combined contraceptives, to analyze the relative risk of cardiovascular eventswithin users and to list the most common circulatory pathologies in these patients.Methods: Three virtual medical databases were surveyed (Pubmed/Medline, BVS/LILACS andScielo). Twelve studies were selected: clinical trials, case reports and articles of indexedmedical periodic originally published in Portuguese and English about synthetic hormones, oralcontraception, coagulation disorders and cardiovascular morbimortality. Results: Syntheticestrogen promotes an increase of some clotting factors’ levels (VII, VIII, IX, X, XII, XIII andfibrinogen), such as a reduction of their inhibitors (S protein and antithrombin). Because of this,etinilestradiol is the component most related to venous thrombosis and ischemic diseases ofbrain and heart. It also improves the releasing of hepatic angiotensinogen, taking to a increase ofblood pressure levels. Conclusions: The prescription of oral combined contraceptives needscriteria, notably due to adverse effects of etinilestradiol. It is recommended to avoid theadministration of these drugs for patients elder than 35 year-old or with risk factors. For thesepatients, the use of progestagen-only pills seems to be safer.

MECHANISMS OF HYPERCOAGULABILITY PROMOTED BY ORAL COMBINED CONTRACEPTIVES Keywords:

contraception , hormone , estradiol , thromboembolism