In women who produce a lot of eggs during IVF, using a GnRH‑agonist (like gonadorelin) to trigger egg release works just as well as the traditional hCG trigger when a small dose of hCG is given later to support the lining. Freezing all embryos and transferring them later eliminates the risk of severe ovarian hyperstimulation syndrome (OHSS) without hurting pregnancy chances.

Using a large patient series, we aimed to evaluate, in a high-responder population, the effect of triggering oocyte maturation with human choriogonadotropin (hCG) or with a gonadotropin-releasing hormone agonist (GnRHa). We analyzed data from 683 intended fresh embryo transfer cycles (ETCs) and 534 frozen-thawed embryo transfer (FET) cycles. The rates of ovarian hyperstimulation syndrome (OHSS), and the embryological, clinical, and newborn outcomes were compared. Considering the type of oocyte maturation trigger and embryo destination, cycles were divided into five groups. Cycles using an hCG-trigger, with progesterone luteal support, had fresh embryo transfer or embryo freeze-all (FA). Cycles using GnRHa/agonist-trigger, with hCG, estrogen, and progesterone luteal support, had fresh embryo transfer or embryo FA. The fifth group consisted of agonist-trigger cycles, without luteal support, that underwent embryo FA. Severe OHSS only occurred in fresh ETC, with the agonist-trigger evidencing a non-significantly lower rate. The FA groups evidenced higher numbers of retrieved oocytes and blastocyst rates. In fresh ETC, the Ag-fresh-hCG group evidenced higher implantation and clinical pregnancy rates. No differences were observed in clinical outcomes after FET, but cumulative clinical outcomes showed higher clinical pregnancy and newborn rates in the Ag-fresh-hCG group. After multivariable logistic regression analysis, these differences were not observed. The present results thus suggest that, in high-responders, the use of a GnRHa-trigger with luteal hCG in a fresh ETC presents similar outcomes relative to the use of an hCG-trigger. Data also suggest that FA should be applied to all suspected OHSS cases. Ovarian hyperstimulation syndrome (OHSS) is a complication of medically assisted reproduction treatments that may require hospitalization. In the presence of high risk to develop OHSS, embryo transfer can be canceled and embryos frozen to be used in a later cycle. Alternatively, a newer drug, an agonist, can be used for egg trigger in association with endometrium special preparation. Some characteristics make women more susceptible to develop OHSS. In this group of patients, we observed that the use of an agonist as egg trigger did not decrease pregnancy outcomes and that the option of freezing all embryos followed by embryo transfer in a later cycle abolished development of OHSS with hospitalization.