Two mainhypotheses are proposed for the development of OHSS:first, estrogen-mediated- as studies have shown thatpatients with high E2 levels of >2500 pg/mL are atincreased risk of OHSS (10); however, there have beenconflicting reports regarding the estrogen hypothesis.Second, corpus luteum mediated hypothesis due to theluteotropic effect, with VEGF mediating downstreampathways (16, 19). The gene discussed is VEGFA; the disease is ovarian hyperstimulation syndrome.