Oocyte maturation triggers in high-responders: a report on 1217 consecutive cycles

Abstract 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 analysed data from 683 intended fresh embryo transfer cycles (ETC) and 534 frozen 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 an 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 number 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 relatively to the use of a hCG-trigger. Data also suggest that FA should be applied to all suspected OHSS cases. Lay Summary The ovarian hyperstimulation syndrome (OHSS) is a complication of medical assisted reproduction treatments that may require hospitalization. In the presence of high-risk to develop OHSS, embryo transfer can be cancelled 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 latter cycle abolished development of OHSS with hospitalization.