Effect of GnRH agonist alone or combined with different low-dose hCG on cumulative live birth rate for high responders in GnRH antagonist cycles: a retrospective study

Background There is insufficient evidence regarding the impact of dual trigger on oocyte maturity and reproductive outcomes in high responders. Thus, we aimed to explore the effect of gonadotropin-releasing hormone agonist (GnRHa) trigger alone or combined with different low-dose human chorionic gonadotropin (hCG) regimens on rates of oocyte maturation and cumulative live birth in high responders who underwent a freeze-all strategy in GnRH antagonist cycles. Methods A total of 1343 cycles were divided into three groups according to different trigger protocols: group A received GnRHa 0.2 mg (n = 577), group B received GnRHa 0.2 mg and hCG 1000 IU (n = 403), and group C received GnRHa 0.2 mg and hCG 2000 IU (n = 363). Results There were no significant differences in age, body mass index, and rates of oocyte maturation, fertilization, available embryo, and top-quality embryo among the groups. However, the incidence of moderate to severe ovarian hyperstimulation syndrome (OHSS) was significantly different among the three groups (0% in group A, 1.49% in group B, and 1.38% in group C). For the first frozen embryo transfer (FET) cycle, there were no significant differences in the number of transferred embryos and rates of implantation, clinical pregnancy, live birth, and early miscarriage among the three groups. Additionally, the cumulative ongoing pregnancy rate and cumulative live birth rate were not significantly different among the three groups. Similarly, there were no significant differences in gestational age, birth weight, birth height, and the proportion of low birth weight among subgroups stratified by singleton or twin. Conclusions GnRHa trigger combined with low-dose hCG (1000 IU or 2000 IU) did not improve oocyte maturity and embryo quality and was still associated with an increased risk of moderate to severe OHSS. Therefore, for high responders treated with the freeze-all strategy, the single GnRHa trigger is recommended for final oocyte maturation, which can prevent the occurrence of moderate to severe OHSS and obtain satisfactory pregnancy and neonatal outcomes in subsequent FET cycles.