Direct evidence of luteal insufficiency in women with habitual abortion.

Plasma levels of progesterone were measured during the luteal phase in 10 of 15 women with clinical histories of at least three spontaneous abortions in the last three gestations, and in 15 healthy nonpregnant women during the same phase of the ovarian cycle. Progesterone values found in the women with habitual abortion were lower (P less than 0.05-0.005) than in the nonpregnant group almost throughout the period of observation. The habitually aborting women who became pregnant again aborted between the seventh and 12th weeks. Their progesterone concentrations were less than 6 ng/ml, 48-72 hours before vaginal bleeding or abortion. These values were compared with those found during the first 12 weeks in normal pregnancy (P less than 0.001). The results suggest a useful method of evaluating the treatment of habitual abortion.