Is endometrial development in the peri-implantation period influenced by high concentrations of luteinizing hormone in the follicular phase?

A retrospective study was designed to examine the relationship between luteinizing hormone (LH) concentrations in the follicular phase and endometrial development in the luteal phase of natural and artificial cycles. Two types of cycle were studied: natural cycles (n = 51) in subjects with unexplained infertility were divided into two subgroups, depending on whether LH measurements in the late follicular phase were based on urine (n = 24) or plasma (n = 27) samples; and artificial cycles (n = 17), produced by the administration of a standard hormone replacement therapy, in two subgroups of women, those with premature ovarian failure (n = 10) in whom plasma LH concentrations were high, and those with unexplained infertility (n = 7) who had their hypothalamic pituitary-ovarian axis down-regulated and in whom plasma LH concentrations were low. The correlation between plasma or urine concentrations of LH in the follicular phase and the results of endometrial biopsy obtained in the luteal phase was calculated. In natural cycles, LH concentrations were similar in those with normal or retarded endometrium, and there was no significant correlation between high LH concentration and retarded endometrial development. In artificial cycles, endometrial development was not different between those with low LH concentrations (down-regulated by Zoladex) and those with high LH concentrations (premature ovarian failure). Endometrial development in the peri-implantation period does not appear to be influenced by LH concentration in the follicular phase. The reported association between high LH concentration and poor reproductive performance cannot therefore be explained by abnormal implantation consequent upon retarded endometrial development.