KISS1 and ovarian hyperstimulation syndrome: Studies in humans and other species have demonstrated that systemic injection of kisspeptins promotes egg maturation and ovulation (Matsui et al., 2004; Caraty et al., 2007; Jayasena et al., 2014), and clinical studies supported the effectiveness of kisspeptins to induce oocyte maturation in patients with high risk of ovarian hyperstimulation syndrome (Abbara et al., 2017).