Clomiphene Citrate as An Adjuvant to hMG Stimulation of the Ovaries in Mid-to-late Follicular Phase and Subsequently Pregnancy Outcome of Frozen-thawed Embryo Transfers

ObjectiveTo compare the results of a novel regimen of human menopausal gonadotrophin (hMG) in combination with clomiphene citrate (CC) in mid-to-late follicular phase with those of a short protocol of GnRH agonist (GnRHa) and hMG used for IVF.MethodsIn the retrospective study, 842 patients undergoing IVF were collected and classified into two groups: hMG in combination with CC in mid-to-late follicular phase (group A, n=319) and short protocol of GnRHa-hMG (group B, n=523). The main outcome measures were ovarian responses in stimulation cycles and pregnancy outcomes in subsequent frozen-thawed embryo transfer (FET) cycles.ResultsIn group A, the serum LH concentration on day 8–10 was similar with that on the day of hCG administration (2.43± 1.92 IU vs 2.51 ± 2.05 IU). The number of mature follicles and oocytes retrieved was significantly lower in group A than in group B while the fertilization rate and the cleavage rate were comparable. The clinical pregnancy rate (47.79% vs 48.04%), the implantation rate (32.49% vs 33.11%) and the cumulative pregnancy rate (58.09% vs 60.22%) were respectively similar in group A and group B.ConclusionshMG in combination with CC in mid-to-late follicular phase results in the same pregnancy outcome as short protocol. The novel protocol may take the advantage of eliminating the occurrence of a premature endogenous LH surge.