Frequently asked questions

Q: What is Factor V Leiden?

Factor V Leiden (FVL) is a genetic mutation that makes you more prone to have blood clots. It is not all that uncommon in caucasians (between 5-15% of the population may have it) but it does not generally cause problems so most people who have it are unaware. It's usually discovered if a person or a close family member has deep vein thrombosis (DVT) or late or recurrent pregnancy loss.

Q: What health implications are there for those with FVL?

You should reduce your risk of forming clots by working on the risk factors that can be changed. You should not smoke, should exercise regularly & watch your weight. You should never take hormone supplements (birth control or hormone replacement therapies) that contain estrogen. If you are traveling or otherwise sitting for long periods of time, you should periodically take breaks to move around as much as possible. You should notify your doctor if you ever have surgery so you can be treated prophylactically with blood thinners. It is important to always stay well hydrated.

Q: Does FVL only affect women?

No, men are just as likely as women to have the mutation. However, many women are diagnosed in connection with a pregnancy because pregnancy is a hypercoagulative state. The body forms clots more easily when pregnant as a natural protection against hemorrhage.

Q: What is the treatment for FVL in pregnancy?

Many women with FVL have healthy pregnancies without treatment (I had 3 full-term babies before I had multiple miscarriages & testing). However, for those with a history of clots or pregnancy loss, most doctors recommend low-dose aspirin therapy and/or daily injections of heparin or lovenox. For patients without a history of clots or pregnancy loss who test positive for the mutation after a family member is diagnosed may be advised to take low dose aspirin, but opinions vary.

Q: I've heard pregnant women aren't supposed to take aspirin?

Generally they are not. Aspirin is a blood thinner and can cause bleeding problems. But, for pregnant women with FVL who clot too much, blood thinners help return the body to a state of equilibrium. Women should not take aspirin to prevent miscarriage unless their doctor has diagnosed or strongly suspects (due to late or recurrent pregnancy loss) that there is a clotting issue.

Q: How is FVL diagnosed?

Specific blood tests can reveal this mutation. FVL is also known as "Activated Protein C resistance". You doctor may simply order the APC resistance test or may order DNA analysis. The DNA test is slightly more accurate (about 2% of APC resistance is not caused by genes) but takes slightly longer to receive results (usually 7-10 day wait).