Luteal progesterone relates to histological endometrial maturation in fertile women

To examine the relationship between endometrial histological maturation and reproductive hormones, we studied 11 fertile women, aged 18-37 yr. All par ticipants had had at least 1 previous pregnancy and cycled regularly, every 25-35 days. Women collected daily, first morning voided urine for measurem ent of estradiol and progesterone metabolite excretion, estrone conjugates (E1c), and pregnanediol glucuronide (Pdg), respectively, throughout the cyc le of study. Hormones were normalized for creatinine. Between 7-9 days afte r home detection of a LH surge (Sure Step), participants underwent an endom etrial biopsy using a small bore (Pipelle) catheter. Tissue was prepared fo r histological and biochemical analyses. The histological analysis is repor ted herein. Endometrium was dated by 3 authors (N.S., D.H., and S.P.), all of whom were blinded to the participant's identity or timing of biopsy with in her cycle. Final dating was agreed upon based upon the method of Noyes e t al. E1c and Pdg were integrated throughout the cycle using the trapezoida l rule, and correlations were sought between deviation from expected histol ogy (based upon urinary hormones and LH surge) and integrated hormone value s. E1c varied over a a-fold range in these normal women, from 1196-2040 ng/cyc le. Pdg excretion was much more variable, ranging from 22-119 mug/cycle. No relationship could be found between histological lagging of endometrial ma turation and lower excretion of E1c. A moderate correlation was observed (S pearman's r = 0.6; P < 0.05) between degree of histological maturation and integrated Pdg. Of two women with evidence of a disparity between gland and stromal development (glands lagging behind stroma by >2 days), one excrete d 24 mug Pdg/cycle, the next to lowest value. We conclude that normal fertile women experience a wide range of hormone co ncentrations in the face of normal endometrial maturation. Progesterone app ears to exert a dose-related effect on endometrial maturation, and the tech niques we used, although relatively crude clinical measures, appeared to be sufficient to detect this relationship.