Field trial results of long-acting injectable medroxyprogesterone acetate as an injectable contraceptive in 1730 patients.

To test the effectiveness of long-acting injectable medroxyprogesterone acetate a a contraceptive 1730 women of the Chiang Mai district of Thailand received 125-200 ng doses of the drug every 3 months for a total of 1234 woman years. To control the irregular bleeding that results from this preparation .5 mg of diethylstilboesterol was administered for a 10 day period each month. There were 6 known method-failures rendering a pregnancy rate of .49 births per 100 woman years. The dropout rate during a 3 month period was 22.3% the majority due to menstrual disorders including amenorrhea or moving away from the district in which the clinic was located Biopsies taken from patients who had been on the drug 1 1 1/2 and over 2 1/2 years showed evidence of constant stromal effect due to persistent progesterone stimulation. This method of contraception was in general well received and highly effective.