A total of 13 participants discontinued from the trial due to an adverse event, comprising 5/202 participants (2.5%) in the GnRH agonist group (COVID-19 infection, n = 1; OHSS, n = 4) and 8/204 participants (3.9%) in the antagonist group (increased progesterone, n = 1; adnexal torsion, n = 1; endometrial disorder, n = 1; hydrometra, n = 1; uterine polyp, n = 1). Here, GNRH1 is linked to endometrial disorder.