Safety of IVF under anticoagulant therapy in patients at risk for thrombo-embolic events.

The objective of this study was to assess the safety of induction of ovulation and oocyte retrieval in patients at risk of thrombosis, necessitating treatment with anticoagulants. Twenty-four patients considered as high risk for a thromboembolic event underwent 73 IVF cycles and 68 oocyte retrieval procedures, and were treated concomitantly with anticoagulation therapy (low molecular weight heparin; LMWH). A subgroup of five patients considered at especially high risk for thrombosis was isolated. These patients were prepared for oocyte retrieval using a controlled spontaneous cycle. All these patients were programmed exclusively for surrogacy. Nineteen women underwent 49 cycles of ovulation induction with gonadotrophins. The average peak oestradiol concentration was 1791 +/- 1420 pg/ml with an average of 13.5 +/- 8.4 oocytes retrieved in each cycle. The five patients from the very high risk group underwent 24 cycles: the average peak oestradiol concentration was 163 +/- 98 pg/ml. In 18, an egg was retrieved and in 14, fertilization was achieved. No bleeding or thromboembolic complications were noted during treatment of both groups of patients. It is concluded that during induction of ovulation in patients at risk for thrombosis, the introduction of LMWH as a cycle protective treatment was not associated with any medical complication. The use of a controlled spontaneous cycle with LMWH is suggested in very high risk patients.