Factor V Leiden as a risk factor for miscarriage and reduced fertility

The Leiden mutation is a recent discovery. It is the main cause of inherite d thrombophilia and has been found in 20-60% of deep vein thrombosis cases. More recently it has been found in a significant number of cases of obstet ric complications attributable to placental thrombosis. Current patient man agement practice for dealing with the Leiden mutation is based mainly on in formation about deep vein thrombosis because there is little information on pregnancy complications. There are no prospective studies examining the ri sk of developing pregnancy complications for Leiden mutation carriers. The aim of this study is to do that by comparing the frequency of unfavourable pregnancy outcomes among carriers with those among controls. The number of women developing miscarriages, intrauterine deaths, or infertility problems among 128 Leiden mutation carriers was compared with the number among 461 controls. The risk of having at least one miscarriage or infertility proble ms was 1.5 times greater for Leiden mutation carriers than controls. This r esult was statistically significant (95% CI 1.2, 2.7). The risk of having a t least two miscarriages or infertility problems was 2.5 times greater for Leiden mutation carriers than controls. This was also statistically signifi cant (95% CI 1.2, 5.13).