PIP: The frequency and time lag associated with cessation of depot-medroxyprogesterone acetate (DMPA) treatment and return of regular ovulation were studied in 6 healthy (aged 20-35 years) Thai women who had used the injectable contraceptive for from 1-2 years (average dose was 150 mg every 3 months). Plasma progesterone was analyzed to determine return of ovulation; 3 ng/ml or greater was considered indicative of ovulation. When the relationship among duration of DMPA use, onset of menstrual bleeding, and significant rise of progesterone levels was determined, there was no correlation between duration of use and onset of first menstrual period; time lags ranged from 2.5-6 months. In addition, the interval of days between onset of first menstrual bleeding and the 3-ng rise of progesterone varied greatly, ranging from 21-119 days. Based on progesterone levels, data indicate that once ovulation was restored, it continued quite regularly, with every fourth or fifth sampling over 30 days revealing elevated progesterone indicative of ovulation; 1 subject was lost to follow-up and 1 had a positive pregnancy test at 120 days after onset of first menses. Though the return to fertility was delayed after DMPA use, it was consistent once achieved.