What risk is added by Factor V Leiden?
QUESTION: Is there is a connection between Factor V Leiden deficiency and HELLP syndrome? ANSWER:
Maybe. There have been dozens of studies that have attempted to answer this question. Some have concluded that yes, women carrying variations on the most common version of the FVL gene are at higher risk, and others have concluded that no, they’re not. Some of this seems to depend on ancestry. The latest large case-control meta-analysis found about a doubling of risk in women of European or Middle Eastern ancestry, but another study of Native American women found no association between these polymorphisms and preeclampsia. Some of this seems to depend on preeclampsia phenotype, or the particular way that your body developed symptoms in response to these genes, rather than the genes themselves. The genes will not always produce the same results in every individual body. Different sorts of preeclampsia can imply different risk factors (for example, women with HELLP may have different underlying conditions from women with eclampsia.) In particular, HELLP does not seem to be associated with underlying genetic predispositions to thrombophilias, but it is also very common for women with HELLP to develop thrombophilia (or to become more likely to clot) during their pregnancies.
If the fetus is carrying a FVL polymorphism or the father carries one, this does not appear to contribute to maternal risk. Because there are so few clear answers, and because treatment for thrombophilias does not seem to lower risk of preeclampsia, the Society for Maternal-Fetal Medicine does not recommend screening women with a history of pregnancy complications for thrombophilias. However, women with symptoms of clotting or a history of clots in pregnancy may need to be anticoagulated to lower their risk of developing clots in pregnancy. If you have a diagnosis of Factor V Leiden, know of a family history of it, or experienced a dangerous clot in the past, bring this up with your care providers and ask for your individual risk and how it will be managed in subsequent pregnancies.