Paternal factor V Leiden and recurrent pregnancy loss: a new concept behind fetal genetics?

In up to 50% of couples affected by recurrent pregnancy loss, no identifiable cause is established. Fetal and maternal factors may be equally important in the establishment and maintenance of the placental/maternal arteriovenous anastomoses. Therefore,the inheritance of thrombophilia-related genes may be an important factor in the pathophysiology of recurrent pregnancy loss. Most of the research on recurrent pregnancy loss and thrombophilia has focused on maternal factors, but little is known about the paternal contribution.

On that basis, we studied the association between inherited paternal thrombophilias and recurrent pregnancy loss in a narrowly selective group of 42 Argentine males from couples that presented without any known risk factors for recurrent pregnancy loss.

The genotypic distributions of factor (F) V Leiden and prothrombin G20210A among cases were compared with those from a reference group composed of 200 Argentine men.

We found a significant difference in the distribution of FV Leiden between both groups (16.7% vs. 3.0%), but no difference was found in the distribution of prothrombin G20210A (2.4% vs.2.0%). Those couples with paternal FV Leiden carriage would be six times more likely to experience recurrent pregnancy loss despite no other apparent cause (OR = 6.47; 95% CI, 2.06–20.39).

We found evidence of an association between the paternal carriage of FV Leiden and the predisposition to recurrent pregnancy loss, thereby supporting the hypothesis that genetic contributions from both parents are essential factors in the development of this obstetric disorder.