Although modern practices, such as increased use of the GnRH antagonist co-treated protocol, are purported to have reduced the risk of OHSS, a recent randomised controlled trial conducted in the UK between 2016-2019 including 619 women, still reported rates of OHSS in women having a fresh transfer at 8.1% (35). Here, GNRH1 is linked to ovarian hyperstimulation syndrome.