ovarian hyper stimulation syndrome in two spontaneous pregnancies

discussion the presence of ohss in spontaneous pregnancy especially in familial pattern may lead us to evaluate some endogenous pathogenic factors. case presentation in this case report, we are going to present two cases of ohss occurring in spontaneously conceived pregnancies. one of the patients mentioned the history of this syndrome in her sister, and the other one confronted with this syndrome in her second pregnancy. both of them referred to the hospital with typical symptoms and signs of ohss. they did not have polycystic ovary syndrome (pcos) and any other problem in pregnancy. thrombophilia workup, tumor markers, renin-aldosterone and thyroid function tests were normal. introduction ovarian hyper stimulation syndrome (ohss) occurs mainly after excessive stimulation of the ovaries by exogenous gonadotropin administered in the context of ovulation induction and in vitro fertilization procedures (iatrogenic ohss). spontaneous ohss is a rare event. such cases would explain other etiologies except ovulation induction. in this case report, we have presented two cases of ohss in spontaneously conceived pregnancies.