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 relationshipbetween luteinizing hormone (LH) concentrations in the follicularphase and endometrial development in the luteal phase of naturaland artificial cycles. Two types of cycle were studied: naturalcycles (n = 51) in subjects with unexplained infertility weredivided into two subgroups, depending on whether LH measurementsin the late follicular phase were based on urine (n = 24) orplasma (n = 27) samples; and artificial cycles (n = 17), producedby 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 thosewith unexplained infertility (n = 7) who had their hypothalamicpituitary — ovarian axis down-regulated and in whom plasmaLH concentrations were low. The correlation between plasma orurine concentrations of LH in the follicular phase and the resultsof endometrial biopsy obtained in the luteal phase was calculated.In natural cycles, LH concentrations were similar in those withnormal or retarded endometrium, and there was no significantcorrelation between high LH concentration and retarded endometrialdevelopment. In artificial cycles, endometrial development wasnot different between those with low LH concentrations (down-regulatedby Zoladex) and those with high LH concentrations (prematureovarian failure). Endometrial development in the peri-implantationperiod does not appear to be influenced by LH concentrationin the follicular phase. The reported association between highLH concentration and poor reproductive performance cannot thereforebe explained by abnormal implantation consequent upon retardedendometrial development.