Freeze All Strategy Versus Fresh Embryo Transfer After GnRH Analogue Trigger

Freeze All Strategy Versus Fresh Embryo Transfer After GnRH Analogue Trigger

Ovarian hyperstimulation syndrome (OHSS) is one of the most dangerous complications of assisted reproduction technology (ART), described in approximatively 3 to 10% of stimulation cycles although an underestimation of the real incidence has been suggested.

The use in clinical practice of GnRH antagonist has made it possible to perform the trigger with GnRH analogues, with the advantage of considerably reducing the risk of OHSS.

The main concerns about the trigger with analogue are about obstetric outcomes, since it may increase the Abortion Rate (AR) and reduce the Ongoing Pregnancy Rate (OPR) due to luteal phase deficiency, and on the other hand about oocyte quality and competence.

While in order to maximize the chance of pregnancy at fresh embryo transfer after GnRHa trigger, several studies have focused on the importance of luteal phase support, other authors suggest that the best strategy is freeze-all: cryopreservation of all the obtained embryos and subsequent single embryo transfers.

However, data about oocyte quality, retrieval rate, pregnancy rate and reduced occurrence of complications such as OHSS, especially on the very first embryo transfer, are still scarce.

Inclusion Criteria:

• patients undergoing ART cycle with antagonist protocol stimulation and trigger with GnRH agonist
• patients are believed at risk of OHSS at time of trigger based on size and number of follicles developed (≥18 follicles with diameter 12 mm at induction).

Exclusion Criteria:

• hypogonadotropic hypogonadism
• other ART protocols
• any patient that underwent freeze-all strategy in order to perform pre-implantation genetic testing (PGT)
• oncological or deferring motherhood freezing procedures