Correlation between estradiol and progesterone in cycles with luteal phase deficiency.

Many studies have been published on luteal phase deficiency, and the emphasis in most of them is on progesterone deficiency. In this study 144 patients (455 cycles) with infertility were studied. The patients were divided into four groups. Group 1 consisted of patients with high estradiol and high progesterone levels in the midluteal phase. Group 2 consisted of patients with high estradiol and low progesterone levels. Group 3 consisted of patients with low estradiol and low progesterone levels. Group 4 consisted of patients with low estradiol and high progesterone levels. As expected, patients in groups 2 and 3 showed a low conception rate with outphased endometrial biopsy. However, group 4, in spite of the normal progesterone levels, had a low conception rate with an outphased endometrium. We conclude that estradiol deficiency during the luteal phase is a major factor in infertility, and replacement therapy with progesterone alone in these patients may not improve fertility.