Dual Trigger vs.GnRH-a Trigger for Elective Fertility Preservation. A Randomized Controlled Trial

Elective oocyte cryopreservation (EOC) has been gaining increasing importance in the last few years, driven by the widespread information regarding the concept of 'age-related fertility decline', as well as the availability of efficient contraception and women's increasing educational and professional aspirations. Considering the similar clinical outcomes regarding live birth rate after vitrified-warmed and fresh oocytes and the proven cost-effectiveness of this approach, oocyte banking is now considered an efficient technique in assisted reproduction.

Previous studies have shown that both patient's age and the number of oocytes retrieved have a significant impact on the cumulative live birth rate (CLBR) in patients undergoing EOC, highlighting the importance of maximizing oocyte yield in these patients.

In all these former reports, final follicular maturation was triggered by one bolus of human chorionic gonadotropin (hCG) or, following recent trends in clinical practice, by a single bolus of Gonadotropin Releasing Hormone agonist (GnRH-a).

More recently, the concomitant administration of both GnRH-a and a bolus of HCG prior to oocyte retrieval (dual trigger) has been proposed as a new strategy for final follicular maturation, aiming to improve oocyte and embryo quality . When compared to HCG trigger, the dual trigger adds the more physiologic follicular stimulating hormone (FSH) and luteinizing hormone (LH) peak provided by GnRH-a. With this approach, several studies have reported an increase in the number of MII oocytes retrieved, as well as in the number of good quality embryos and improved pregnancy outcomes in different subpopulations of infertile patients.

Nowadays, the standard of care in patients undergoing a freeze-all approach, either for oocyte or embryo cryopreservation, is final follicular maturation with GnRH-a due to its more physiologic and shorter surge of both LH and FSH, terminating 24h after its onset, and reducing the risk of ovarian hyperstimulation syndrome (OHSS). So far, no study has compared the dual trigger approach to the use of a single bolus of GnRH-a. By adding HCG activity and, therefore, generating higher intracellular cyclic adenosine monophosphate (cAMP) accumulation, an amplification of the steroidogenic response of the pre-ovulatory follicle might be achieved with the dual trigger when compared to the GnRH-a trigger alone.