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

Objective: To evaluate the luteal phase in women with rigorously defined unexplained infertility. Design: Prospective study. Setting: National Center for Infertility Research at Michigan. Patient(s): Evaluation of 1,885 women with infertility identified 12 women who met the rigorously defined criteria for unexplained infertility: [I] infertility of greater than or equal to 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. Main Outcome Measure(s): Pattern of follicular growth rate and luteal phase hormonal profile. Result(s): 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 Ep:P also was significantly greater in women with unexplained infertility than in fertile controls. Conclusion(s): Women with rigorously defined unexplained infertility have subtle hormonal anomalies during the luteal phase when compared with fertile controls.