Abstract

PIP: Various aspects of injectable prolonged-action steroid contraceptives are reviewed with special emphasis on the effectiveness of depo- medroxyprogesterone (depo-provera) and norethisterone enanthate (NE). Both preparations have progestogen activity. Depo-provera was 1st used for the treatment of endometriosis and threatened abortion. As a contraceptive, 150 mg depo-provera is given every 90 days (once every 3 months). NE is also given 200 mg during the 1st 5 days of a cycle; injections are repeated 2 months later and then every 3 months. The incidence of pregnancy following depo-provera use did not exceed 1/100 women-years. Clinical trials of NE indicated the incidence of pregnancy ranging from 1-3.6/100 women-years (depending upon drug administration schedule). The contraceptive effect of both depo-provera and NE was shown to be associated with inhibition of ovulation. The majority of women treated with depo-provera or NE developed various disorders of the menstrual cycle. Amenorrhea development was found to depend upon duration of administration, and was more frequent after depo-provera than after NE. Metabolic effects of depo-provera and NE included decrease in the blood level of cholesterol in high-density lipoproteins, and an increase in the fasting levels of glucose and insulin. Depo- provera did not affect liver function. Epidemiological studies did not show an increase in cancer incidence following the use of depo-provera. Restoration of fertility occurred about 5.5 months after termination of depo-provera administration. Injectable contraception recommended primarily in young women who want to increase the intervals between childbirths. Women older than 40 years should use other methods of contraception.