Luteal hormonal profile of oocyte donors stimulated with a GnRH antagonist compared with natural cycles.

The effect of gonadotrophin-releasing hormone (GnRH) antagonist treatment on luteal phase hormonal profile has not yet been fully investigated. Cycle characteristics of 23 fertile donors stimulated with recombinant FSH and the GnRH antagonist, ganirelix 0.25, for IVF and receiving no kind of luteal supplementation were compared with control, natural cycles. Luteal luteinizing hormone (LH) serum concentrations as well area under the curve (AUC) for LH were significantly higher in natural cycles. In addition, luteal phase length was longer in natural cycles compared with donor cycles. Luteinizing hormone values dropped in the luteal phase of the stimulated cycles, with the lowest values being observed in the mid-luteal phase. AUC for progesterone in the luteal phase was significantly higher in the stimulated cycles compared with natural cycles (P < 0.001). Low LH serum concentrations and shortened luteal phase indicate the need for luteal phase supplementation in GnRH antagonist IVF cycles.