After oocyte donation 18 pregnancies were established in 17 patients with the absence of ovaries. Eight patients were delivered of nine healthy infants including one set of twins, six pregnancies were progressing normally, and four pregnancies were aborted. Four pregnancies were established after transfer of frozen-thawed embryos. In the simulated luteal phases, replaced with estradiol valerate and progesterone, pregnancies could be established and maintained as indicated by the profile of serum human chorionic gonadotropin concentrations. Weekly determinations of serum 17 beta-estradiol levels indicated significantly higher values at 7 weeks' gestation, as compared with week 5. This observation precludes that the luteoplacental shift occurred before 7 weeks' gestation. The weekly serum determinations of progesterone were significantly higher week 9, as compared with week 5. Two pregnancies were achieved after the vaginal administration of micronized progesterone.