Unexplained infertility: Evaluation of the luteal phase; results of the National Center for Infertility Research at Michigan

To evaluate the luteal phase in women with rigorously defined unexplained infertility. Prospective study. National Center for Infertility Research at Michigan. Evaluation of 1, 885 women with infertility identified 12 women who met the rigorously defined criteria for unexplained infertility: [1] infertility of ≥24 months duration, with no male factor, anatomic-functional disorders of the reproductive tract, or immunologic infertility; [2] normal body mass index (BMI); [3] ovulatory cycles ranging from 26 to 32 days; [4] normal luteal phase determined by endometrial biopsy; and [5] normal baseline hormonal profile. Controls (n = 12) were healthy, parous women with normal ovulatory cycles, normal hormonal screen, and were matched for age and BMI to patients. Pattern of follicular growth rate and luteal phase hormonal profile. Women with unexplained infertility did not differ in menstrual cycle characteristics, follicular growth rate or mean preovulatory follicle diameter, or endometrial biopsy dating. The mean levels of P tended to be lower in the unexplained infertility group throughout the luteal phase, but only the midluteal interval reached statistical significance. Luteal phase mean integrated P or urinary PDG levels of unexplained infertility women did not differ from those of fertile controls. The ratio of integrated E 2:P also was significantly greater in women with unexplained infertility than in fertile controls. Women with rigorously defined unexplained infertility have subtle hormonal anomalies during the luteal phase when compared with fertile controls.