Researchers tried different ovulatory triggers to replace HCG in high responders and PCOS patients as a trial to reduce the OHSS risk in such patients. In 1990 Gonen et al. proposed the use of the flare of the GnRH agonist trigger as a way to induce an endogenous LH and FSH surge mimicking normal physiology. At first studies found worse reproductive outcome due to defective luteal phase support cause by the short lived LH surge induced by the agonist trigger which failed to support early pregnancy.
Furthermore, the agonist trigger had a suboptimal response incidence around 5 %, this was specially observed in patients with low LH level at start of stimulation as patients with hypogonadotrophic hypogonadism and those who received combined oral contraceptives for a long period prior to stimulation. However, later studies proved that the GnRH agonist trigger alone or added to HCG has a positive effect on the embryological outcome of ICSI cycles. Similarly, multiple studies suggested positive effect of the dual trigger on oocyte and embryo quality.
Moreover, the dual trigger had a benefit in its ability to overcome the suboptimal response to the agonist trigger as well as possible benefit on the quality of oocytes and embryos.
The benefit of the dual trigger on the embryological and reproductive outcome in normal and poor responders in fresh cycles over hCG alone or agonist trigger alone was supported by many studies in recent literature.