Internal jugular vein thrombosis caused by resistance to activated protein C as a complication of ovarian hyperstimulation after in-vitro fertilization

We present a case of a 24 year old woman who became pregnant(twins) after human menopausal gonadotrophin (HMG)-induced ovarianstimulation, in-vitro fertilization (IVF) and subsequent embryotransfer. She developed a right internal jugular vein thrombosisas a complication of severe ovarian hyperstimulation syndrome(OHSS) 28 days after embryo transfer. The thrombosis developedin spite of anticoagulation with low-dose heparin. Later a resistanceto activated protein C (APC) or Dahlbäck disease was diagnosed.Due to a new test procedure (accelerin inactivation test), thediagnosis was possible even under anti-coagulation treatment.The coincidence of hyperstimulation and internal jugular veinthrombosis with the concurrent diagnosis of resistance to APChas not been published previously. The benefit of general screeningfor resistance to APC before admission to the IVF programmeshould be weighed. Targeted selection of a group of high-riskwomen would therefore be made possible.