GNRH1 and ovarian hyperstimulation syndrome: For example, GnRH agonist treatment is associated with adverse drug reactions related to hypoestrogenism (mild to severe hot flushes and vaginal dryness), ovarian cysts during the initial phase of treatment, and a higher incidence of OHSS, compared with treatment with a GnRH antagonist protocol, especially in predicted normal to high responders (Al-Inany et al., 2016; Lambalk et al., 2017; Toftager et al., 2017; Yang et al., 2021).