Return of fertility after discontinuation of depot medroxyprogesterone acetate and intra-uterine devices in Northern Thailand.

796 Thai women who stopped using the long-acting injectable contraceptive 'Depo-Provera' (medroxyprogesterone acetate) and 125 women who had an intra-uterine device removed to have a planned pregnancy were followed-up to ascertain the delay between conception and the end of contraception, and to determine the proportion of women who did not conceive in the 2 years after discontinuation. The median delay before conception was 5.5 months plus the estimated duration of the effect of the last injection of depo-provera and 4.5 months after discontinuing the IUD. Since depo-provera acts for approximately 15 weeks, women can except a median delay to conception of around 9 months after their last injection. The proportions of women who did not conceive within 1 year and within 2 years of stopping contraception by the two methods were similar. There was no evidence to suggest that prolonged use of depo-provera increases the delay before conception, and the return of fertility among never pregnant ex-users resembled that of ever pregnant ex-users.