Clinical study of a monophasic pill containing 20 microg ethinylestradiol and 150 microg desogestrel in Thai women.

Objectives: To evaluate the contraceptive reliability and clinical effects of a monophasic oral contraceptive containing 20 microg ethinylestradiol and 150 microg desogestrel (Mercilon) in Thai women.

Method: The study was carried out at the Family Planning Clinic of King Chulalongkorn Memorial Hospital, Bangkok, Thailand. One hundred and forty six healthy women of fertile age were enrolled and treated with the study oral contraceptives for 12 cycles. Clinical data of vaginal bleeding, side effects, blood pressure and body weight were assessed periodically.

Results: One thousand four hundred and twenty five cycles were evaluated. No conception occurred. The cycles were almost regular. The incidence of irregular bleeding was highest in the first cycle, after the third cycle, the value was below 4 per cent. Side effects were very few. There was no change in blood pressure. A slight decrease in mean body weight was observed.

Conclusion: The oral contraceptive containing 20 microg ethinylestradiol and 150 microg desogestrel has high contraceptive efficacy, good cycle control and minimal side effects.