Midluteal immunoreactive α-inhibin serum concentrations as markers of luteal phase deficiency

The present prospective clinical study was undertaken to determine the usefulness of midluteal phase serum immunoreactive alpha-inhibin concentrations as markers of luteal phase deficiency and whether they are better indicators of biopsy confirmed luteal phase defect than serum progesterone. Consecutive patients (n = 138) with regular menstrual cycles attending our Infertility Clinic (experimental group) and 15 fertile women who were requesting contraception and had regular menstrual patterns (control group) were included. In all women (patients and controls), basal body temperature, midluteal serum concentrations of oestradiol, prolactin, progesterone and immunoreactive alpha-inhibin, and premenstrual endometrial biopsy were used in the same cycle to assess luteal function. Out-of-phase secretory endometria were detected in 15 of the 138 patients. Thus, hormonal concentrations were compared between the following three groups of women: group 1 (n = 15), infertile patients with defective secretory endometria; group 2 (n = 123), infertile patients with normal secretory endometria; and controls (n = 15), fertile women with normal secretory endometria. Midluteal serum concentrations of progesterone, immunoreactive alpha-inhibin, oestradiol, and prolactin of the two groups studied were similar to those of the control group of fertile women. Our results indicate that midluteal serum inhibin determination does not accurately reflect histological maturation of the endometrium and it is not a better indicator of endometrial luteal phase deficiency than midluteal serum progesterone concentration.