Recent studies have shown a positive correlation between spliced XBP1 (induced by ER stress) and ovarian hyperstimulation syndrome (OHSS), a major complication during infertility treatment that is mainly characterized by increased capillary permeability (Elchalal and Schenker, 1997; Takahashi et al., 2016). Here, XBP1 is linked to ovarian hyperstimulation syndrome.