Protocol-Specific Outcomes of GnRH Agonist Use in Luteal Phase Support During Frozen Embryo Transfer Cycles

Recent data comparing natural cycles and artificial cycles in frozen embryo transfer (FET) showed an equivalent LBR when optimized luteal phase support (LPS) was used. Of the suggested methods is the use of GnRH agonists as part of LPS. We aim to study whether the addition of GnRH agonists as LPS in FET cycles increases the live birth rate (LBR) and decreases the miscarriage rate (MR).

A retrospective analysis was performed for 140 FET cycles, which were divided into two groups. The study group in which a GnRH agonist was used (AG) at the time of embryo transfer included 66 cycles, whereas the control group (NAG) included 74 cycles in which the use of GnRH agonist was not described.

The implantation rate was greater in the AG (69/112 (61.6%) vs 60/124 (48.4%), p= 0.0413). The LBR was greater in the AG than in the CG but did not reach statistical significance (40/66 (60.6%) vs 35/74 (47.3%), p= 0.114). The MR was similar between the 2 groups (6/66 (10%) vs 5/74 (6.7%), p= 0.61). The subanalysis per FET protocol revealed that there was no difference in the LBR between the AG-medicated and NAG-medicated cycles (15/34 (44.62%) vs (36/65 (55.38%), p=0.1984) or between the AG-ovulation induction and NAG-ovulation induction FET cycles (21/32 (65.63%) vs 6/9 (66.67%), p=0.1985).

The use of a GnRH agonist as an add-on for LPS in FET cycles numerically increased the LBR without reaching statistical significance despite significantly improving the implantation rate. MR were not affected. This potential beneficial effect was comparable between the artificial and ovulation-induction FET cycles.