Background and objectives: Women undergoing assisted reproductive procedures, such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), fail to achieve pregnancy in approximately 70% of cases. Postulating that among the possible causes of failure of embryo implantation might be an impairment of the uteroplacental circulation due to hypercoagulability in the mother, we investigated the association between thrombophilia and failure to achieve pregnancy after IVF or ICSI.
Design and methods: A case-control study was carried out in 234 women undergoing IVF or ICSI and in 234 women who, in the same period, conceived naturally. Thrombophilia due to mutations in genes encoding coagulation factor V (G1691A), prothrombin (G20210A), methylene-tetrahydrofolate reductase (C677T) and the presence of antiphospholipid antibodies was searched for.
Results: The prevalence of factor V, prothrombin and methylene-tetrahydrofolate reductase mutations was similar in the 162 women who failed to achieve pregnancy after IVF or ICSI and in control women (5% and 2% for factor V G1691A, odd ratio 2.4, 95% CI 0.8-7.4; 3% and 6% for prothrombin G20210A, odds ratio 0.5, 95% CI 0.2-1.5; 19% and 20% for homozygous methylene-tetrahydrofolate reductase C677T, odds ratio 1.0, 95% CI 0.6-1.6). Nor was any association found when women who failed to achieve pregnancy were divided according to the total number of assisted reproductive procedures, age, type of procedure and cause of infertility. Antiphospholipid antibodies were not detected in any of the women.
Interpretation and conclusions: This study provides no evidence for an association between maternal thrombophilia and failure to achieve pregnancy after assisted reproductive procedures. Routine anticoagulant treatment in women undergoing assisted reproductive procedures is not warranted.