Plasma steroid and gonadotrophin profiles in ovulatory but infertile women.
A group of twelve patients with a history of infertility lasting at least 2 years despite evidence of regular ovulatory cycles, were selected from an Infertility Clinic after thorough investigation had revealed no other obvious cause for their infertility. Daily plasma gonadotrophin and steroid concentrations were measured in twenty cycles from these women and the results compared with the hormonal profiles obtained from a group of eleven control 'normal' women. No significant differences were found in the concentrations of LH, FSH or oestradiol although plasma progesterone concentrations were significantly lower in the infertile women, particularly during the first half of the luteal phase. In the absence of any other demonstrable defect, it was assumed that the decreased progesterone secretion was directly or indirectly implicated in the pathogenesis of their infertility, and a number of therapeutic regimes (progesterone supplementation of the luteal phase or additional stimulation by either anti-oestrogens or exogenous gonadotrophins) were assessed for their efficacy in correcting this defect. Although plasma progesterone concentrations after most of these regimes were significantly increased, none of the patients in this series conceived.