Delayed onset of luteinization as a cause of infertility.

Two groups of infertility patients with regular cycles and apparently normal ovarian function were studied. In group I (n = 28) the infertility could be explained satisfactorily either by tubal occlusion or by infertility of the husband, or the women became pregnant within a few months. In group II (n = 32) no explanation was found for the infertility. Significantly fewer ovulation stigmata were present at laparoscopy in group II than in group I (P less than 0.05). In group I the basal body temperature (BBT) (P less than 0.001) and the plasma progesterone concentrations (P less than 0.05) were significantly elevated on the 1st day following the luteinizing hormone (LH) peak. In group II, THE BBT was slightly elevated on the 1st day following the LH peak (P less than 0.05), but the increase in the plasma progesterone concentrations occurred only on the 2nd day following the LH peak. In four women the onset of the BBT rise followed a normal LH peak with delays respectively, of 3, 4, 4, and 5 days, and in two women no LH peak occurred immediately prior to the onset of the BBT rise. The datings of the endometrial biopsies in these patients were in phase with the onset of the BBT rise but not with the LH peak. It is concluded that anovulation with in situ luteinization may be a rather frequent cause of infertility in regularly cycling women. A hypothesis about the mechanism of anovulation with in situ luteinization is proposed.