Low Molecular Weight Heparin (LMWH): Enoxaparin as Adyuvant of In Vitro Fertilization Techniques (IVF) in Women with Recurrent Implantation Failures (RIF): Obstetric and Perinatal Outcome: Preliminary Report

Background: The success of assisted reproduction technologies (ART) is far from optimal. Couples who failed to conceive after multiple ART cycles often seek for new laboratory tests and/or treatment options. Hematologic aspects of ART include thrombophilia tests and/or the use of LMWH in RIF. Investigation and treatment of thrombophilia has become a common practice in RIF but there seems to be no association. Heparin might improve implantation rates in patients undergoing ART through mechanisms not related to anticoagulation. Moderate quality of evidence studies showed that LMWH can enhance pregnancy rates in women with RIF.

Objectives: The aim of this study was to provide a comprehensive follow-up of a selected group of patients with RIF in whom LMWH was indicated as adjuvant in a next IVF procedure.

Material and Methods: Medical charts of women referred to the hematological bureau were revisited. Selected patients (n 10) with RIF (7 with their own oocytes and 3 with own + ovodonation) from only one fertility clinic were included, Mean age 39(range 31-41). Enoxaparin 40 mg/dose was initiated 3 days before embryo transfer (ET) if embryo was frozen or by egg donation if not after ET and continued all pregnancy. Hereditary thrombophilia was not routinely studied and 6 had occasional positive antiphospholipid antibodies.

Results: There were 11 pg.with a medium of 2 cycles with LMWH:3 early abortions; 2 twin pg: weight 2310/2650 and 2410/2460 and 6 singleton pg: mean gestational age at delivery: 37, 5 weeks and mean weight: 3300 grams.

Comments and Conclusions: In a selected group of women with clear RIF on unknown cause the use of LMWH as adjuvant was helpful in enhance pregnancy rates with a good perinatal outcome. Empirical administration of LMWH in RIF is supported by weak evidence, our results adds more information and highlights the importance of well-designed randomized trials to confirm these results.