Ovarian hyperstimulation syndrome (OHSS) is one of the most serious complications of controlled ovarian stimulation. This syndrome is more usually seen in patients with polycystic ovaries (especially those women with polycystic ovarian syndrome) and in those women with high AMH. Although there are several approaches to reduce the incidence of OHSS, the use of GnRH agonist to trigger the ovulation (replacing the traditional hCG) is one of the most effective (although a complete elimination of OHSS does not exist).

The problem is that many studies showed that using GnRH agonist decreases not only the OHSS incidence but also the pregnancy rate. This is true when doing a fresh embryo transfer. In the past, when freezing embryos was not as good as nowadays, there were lots of approaches trying to improve the success rates when giving GnRH agonist. However, as now we have great freezing techniques, and as there is huge evidence supporting the advantages of performing a frozen-thawed embryo transfer, now it is very easy to decide using the GnRH agonist, reducing the OHSS incidence and keeping the success rate by postponing the embryo transfer to the following cycle.

There are some author that still suggest the use of other alternatives. Using GnRH agonist and doing a frozen-embryo transfer is a great therapeutic option: both safe and effective.