Pregnancy, Hormonal Contraception, and Postmenopausal Estrogen Replacement Therapy

Abstract

This chapter reviews the available data on the risk of stroke related to ovarian steroids, both endogenous (pregnancy) and exogenous (hormonal contraception and postmenopausal estrogen replacement therapy). Special diagnostic and therapeutic issues related to stroke and pregnancy are also discussed. Estrogen replacement therapy (ERT or unopposed estrogen) or hormone replacement therapy (HRT) is widely used by postmenopausal women to control vasomotor symptoms and to prevent osteoporosis and coronary heart disease. In general, the natural conjugated estrogens used in ERT and HRT are taken at doses which are 10 to 25% of the potency of the synthetic estrogens in low-dose oral contraceptions. Also the progestins used most commonly in HRT (medroxyprogesterone acetate, micronized progesterone) are thought to be less potent than the 19-norprogestins used in most OCs. Population-based reports indicate that up to 50% of women in the United States may be exposed to ERT or HRT during their lifetime. As stroke is a significant cause of morbidity and mortality in postmenopausal women, any association between ERT and/or HRT and stroke risk would have an immense public health importance.