Ovarian hyperstimulation syndrome and thrombotic events

Ovarian hyperstimulation syndrome (OHSS) is one of the most important complications of ovarian stimulation with severe morbidity and is still a threat to every patient undergoing ovulation induction. This manuscript reviews the current evidence regarding the relationship between OHSS and thromboembolism in infertile patients undergoing ovarian stimulation published in the world literature. The PubMed Database was searched for publications on reported cases of OHSS and thromboembolic phenomenon published between 1965 and 2013. One hundred and forty cases of OHSS and thromboembolic phenomena were retrieved. The vascular accident had already occurred in the first cycle of treatment among 119 women (85%), at early stage of OHSS in 43% and late stage in 57% of cases. Venous thrombotic events were recorded mostly in unusual sites, jugular, and subclavian veins, with 69 and 38 thrombotic events, respectively. Coagulation status was found at 86 of the 140 cases (61%). Fifty-three of the pregnant patients (68%) delivered singleton births and 47% had preterm deliveries, and termination of pregnancy was indicated in 11 cases (14%). The most serious complication associated with OHSS is thrombotic phenomena as shown in the present review of 140 cases, world data, on both arterial and venous side. Thromboprophylaxis should be initiated in patients with thrombophilia and who develop moderate-to-severe OHSS.