Citation

Okada H, Honjo H. Rinsho Fujinka Sanka 1988; 42(11): 991-996.

Copyright

(Copyright © 1988)

DOI

unavailable

PMID

12283953

Abstract

Biological effects of oral contraceptives are discussed in connection with prospective legalization of pills in Japan. Gestoden and norgestimate, which are likely to be introduced to Japan soon, are progestogen which significantly inhibits ovulation without negative estrogen action. Ever since Ministry of Health published "Research Group Report on Methods of Clinical Evaluation of Oral and Other Contraceptives" and "Guidelines for Methods of Clinical Evaluation of Oral and Other Contraceptives" in November, 1986, Japan is slowly moving toward legalizing oral contraceptives. Clinical testing is currently being conducted on low dose pills. Table I shows code numbers of pills being tested, their makers, phasicity, progestogen and estrogen contents tablet and number of days to take pills. Table II shows inhibition of ovulation by levonorgestrel in different doses. Chart I shows progestogens used in pills; Chart II, estrogen used in pills. When 0.03 mg, 0.05 mg, 0.1 mg and 0.15 mg of levonorgestrel are administered to healthy female subjects for 21 days starting on the 5th day of menstruation, complete inhibition of ovulation occurs if dosage is 0.05 mg and over, and inhibition fails to occur if dosage is 0.03 mg or below. The use of low dose triphasic pills inhibits sperm penetration by increased cervical mucus activity and its contraceptive effect is 99.9%. Pills' health benefits include improved regularities of menstruation, decreased loss of blood and prevention of anemia, less chances of pelvic inflammation and extrauterine pregnancy, endometrial and ovarian cancers. Preventive effects on endometritis and benign mammalian cysts are also reported. Pills' side-effects include slightly increased risk of cervical and breast cancers, that of benign liver cell adenoma, that of venous thrombosis due to estrogen activity, some risks of arteriosclerosis and ischemic heart disease. Pill users over 35 years of age who smoke are the highest risk group for circulatory organ disorders.

Language: ja