Evaluating thrombophilia in severe ovarian hyperstimulation syndrome

Ovarian hyper stimulation syndrome (OHSS) and its consequences, especially thromboembolic events, are of the most dangerous complications of assisted reproductive technologies (ART). It is unclear whether a thrombophilic predisposition or changes in blood components during clinical presentation of OHSS increase thrombotic risks. Testing for certain thrombophilias in selected high risk patients may help risk assessment and decision-making about prophylactic measures. In this study carried out in April 2010 to March 2011, 108 in vitro fertilization candidates with ≥20 follicles following ovarian stimulation were recruited. Protein S, protein C, antithrombin, lupus anticoagulant and anticardiolipin antibodies were measured. Blood tests were compared between severe and non-severe OHSS groups and their changes were traced after onset of clinical OHSS in 43 patients presenting with severe symptoms by repeating the tests at hospital admission. Mean protein S activity was lower in severe OHSS group (101.7±16.3 vs. 118.4±17.0; P<0.001). After clinical presentation of severe OHSS, this level decreased to 91.6±20.1 (P<0.001). Antithrombin levels decreased 2.09% after the onset of symptoms in the group with severe OHSS, but this difference was not statistically significant (P=0.051). Protein C, lupus anticoagulant and anticardiolipin antibodies were not correlated to severe OHSS development. Patients with relatively lower protein S activity were at higher risk for the development of severe OHSS, and its dangerous consequences. During clinical OHSS presentation, protein S decreased even more, and patients were more vulnerable to hypercoagulability states. These points should be kept in mind in risk assessment and adoption of prophylactic strategies.