Abstract

PIP: Hormonal contraceptives, in the form of combined estrogen-progestin oral contraceptives, are the most efficient, readily acceptable, and convenient method of contraception available. Of the two synthetic estrogens in oral contraceptives, ethinyl estradiol is the more potent and is now more frequently used. All progestins used in currently available combined oral contraceptives are derived from 19-norsteroids. Increasingly, the steroid dose has been reduced in conformity with the pharmacalogical rule of prescribing the minimum dose for the desired effect, observance of which has been accompanied also by a possible reduction of some of the systemic side effects. Synergism between progestin and estrogen has been demonstrated in the case of lynestrenol and levonorgestrel. This is of great importance in ensuring an adequate margin of contraceptive effectiveness with these currently favored low-dose formulations. Formulations containing levonorgestrel are extensively used, are relatively free from side effects, and allow a more rapid return of ovulation on their withdrawal. Indications of lower dose formulations, where acceptable to the patient, are 1) a preferable method of fertility regulation when functional gynecological disorders are present; 2) less evident subjective symptoms such as headache, weight gain, and depression; and 3) some protection against rheumatic and thyroid conditions, and reduction of benign breast conditions. Occurrence of liver tumors is a contraindication but its significance is difficult to assess because of its rarity. Cardiovascular complications and thromboembolic disease are increased risks when oral contraceptives are used with other adverse health factors, after prolonged use, and for women over 35. The possibility of drug interaction is recognized with lower dose formulations and ancillary contraceptive measures should be taken; in the longer term, a higher dose formulation is indicated.