Abstract

PIP: The forms of administration, mechanisms of action, side effects and complications, and other aspects of female hormonal contraception are set forth in this "lesson" for medical students. Female hormonal contraception has been in use for over 30 years and is used by more than 150 million women worldwide. Oral contraceptives suppress the preovulatory peak of follicle stimulating hormone and luteinizing hormone, preventing ovulation and follicular maturation. Progestins render the cervical mucus impermeable to sperm and modify the endometrium so that it will no longer support implantation. The synthetic estrogen ethinyl estradiol is used in most combined oral contraceptives (OCs). Among the numerous progestins in use are the newer desogestrel, gestodene, and norgestimate, which have fewer androgenic and metabolic effects than did the 1st generation. the different forms of administration of hormonal methods include combined OCs, oral preparations containing low doses of progestin continuously administered or high doses continuously or discontinuously administered. Intramuscular injection of progestins and the so-called "morning after" postcoital pills are less often prescribed. The combined preparations may be monophasic, biphasic, triphasic, or sequential. Sequential preparations should be avoided because of the hyperestrogenic climate they induce. The low-dose progestin preparations are indicated for women with contraindications to synthetic estrogen. They must be taken at the same time each day and have a relatively high rate of side effects, especially ovarian and breast cysts and irregular bleeding. High-dose progestin preparations have significant metabolic effects and are indicated primarily for patients with gynecological problems such as fibromas and endometriosis. Intramuscular injection of medroxyprogesterone acetate every 3 months is effective but has the same side effects as high-dose progestins. It is indicated primarily for patients unable to control their own behavior. The hormonal methods are all highly effective in preventing pregnancy when correctly administered. Side effects may be minor problems, such as nervousness and nausea, that are usually of short duration. the more serious side effects, including modifications of lipid or carbohydrate metabolism, hemostasis, blood pressure, or hepatic functioning and cardiovascular effects, have been reduced with the new lower dosed formulations. Absolute contraindications to hormonal contraception include undiagnosed vaginal bleeding or amenorrhea, history of thromboembolic or cerebral vascular accidents, severe cardiopathy or hypertension, hyperlipidemia, hepatopathy, hormonodependent cancer, pituitary tumors, porphyria, and severe mental problems. Relative contraindications impose the need for careful monitoring and follow-up. The practitioner should be aware of the possibility of interactions between OCs and certain other drugs.