After a secondary analysis of ESTHER-1, Fernández-Sánchez et al. confirmed that individualized dosing with follitropin δ significantly reduced moderate/severe OHSS and/or the need of OHSS preventive interventions in patients undergoing up to three COS cycles, and the greatest benefit was observed in patients in the highest AMH quartile, those with the maximal risk of severe OHSS [43]. This evidence concerns the gene AMH and ovarian hyperstimulation syndrome.