In vivo metabolism of H3-medroxyprogesterone acetate in pregnant and nonpregnant women and in the fetus.

PIP: 3 pregnant and 3 nonpregnant controls received orally 484 mcc tritiated-medroxyprogesterone acetate mixed with 36 mg of the nonlabeled compound. A 7th woman (pregnant) also received 20 mcc carbon-14-progesterone concomitantly. The 4 pregnant women ranged from 11 to 22 weeks of gestation and were scheduled for therapeutic abortions. The radioactivity in blood and urine was followed by sequential analysis to demonstrate the uptake and excretion of the compounds. It was found that far greater excretion occurred in the pregnant than in the nonpregnant patients the first 24 hours: .25%, .4%, and .31% dose was recovered from the nonpregnant women; 4.3%, 3.1%, 3.56%, and 4.02% dose was recovered from the pregnant women who were 11, 12, 16, and 22 weeks gestation, respectively. The labeled distribution of the drugs in the ovary, myometrium, placenta, and decidua was studied. The fetal tissues and fluids were also assayed for radioactivity. The ratio of the tissues to fluids in dpm/gm or ml to dpm/ml of whole blood was calculated. The fetal adrenal to blood ratio was by far the greatest (18,560 vs. 833, 17,300 vs. 795, 25,499 vs. 950, and 37,907 vs. 1050 dpm/gm for 11, 12, 16, and 22 weeks of gestation, respectively).^ieng