Effects of natural progesterone on the morphology of the endometrium in patients with primary ovarian failure.

In 43 patients without ovaries, endometrial biopsies at day 21 of 75 substituted cycles were studied by light and electron microscopy. The morphology of the endometrium was compared after oral, vaginal or intramuscular administration of progesterone, and correlated with the serum levels of 17-beta oestradiol and progesterone and the pregnancies obtained after oocyte donation. After vaginal application of micronized progesterone, endometrial morphology closely matched that of a natural cycle. This therapy was able to support two ongoing pregnancies. No adequate endometrial response was noted after oral ingestion of progesterone. The maturation of the endometrium after intramuscular injections of progesterone in oil was heterogeneous. It was concluded that the vaginal route for administering micronized progesterone can be advised as the treatment of choice in patients without ovarian function.