Objective
To assess the effect of an additional single mid-luteal dose of gonadotropin-releasing hormone agonist (GnRHa) on pregnancy and perinatal outcomes in hormonally substituted frozen embryo transfer (FET) cycles.
Study design
A prospective interventional pilot study. Women scheduled for FET were randomly selected to receive standard hormonal replacement therapy (HRT) for endometrial preparation or HRT with a single additional subcutaneous dose of 0.1 mg triptorelin at the time of implantation. If FET was not followed by a pregnancy, women with surplus embryos were scheduled for a single second attempt in a crossover setting. Altogether, 144 FET cycles were analyzed. The carryover effect was tested using a logistic regression model. Logistic regression analysis for binary variables was applied with generalized estimation equation extension to account for dependence among repeated treatments.
Results
The live birth rate (LBR) was 9.8 percentage points higher and the miscarriage rate 14.7 percentage points lower in the intervention group (n = 72) than in the control group (n = 72), but the differences did not reach statistical significance. Implantation and clinical pregnancy rates were comparable between the groups. No congenital malformations or differences in the median birth weight of newborns were detected.
Conclusions
Observable but statistically insignificant difference in LBR and miscarriage rate favoring luteal phase GnRHa support was detected. Further, no malformations or effect on fetal growth were observed. Larger studies are needed to confirm the results of this pilot study.