Facts About Factor V

If you're going to have a thrombophiliac mutation, Factor V Leiden is the one to have. It's relatively common (possibly carried by as much as 15% of the population) and largely asymptomatic.

What Is Factor V?
Everyone has Factor V. It's a protein in the blood that is a part of normal clotting process in the body. When damage occurs to a blood vessel, the platelets swimming around in your veins swarm to the injury and produce something called fibrin, which patches up the leak. Factor V is one of the clotting factors that helps create the fibrin.

When the fibrin patch is finished, another protein--activated protein C (APC)--swings into action to stop the Factor V from creating more unnecessary fibrin.

What Is Factor V Leiden?
Factor V Leiden is a funky version of Factor V that is resistant to the APC. So, if you have Factor V Leiden, when APC is screaming to stop making fibrin because the clot needed to repair your injury is plenty big, you just keep right on clotting. The bigger the better.

What's the Big Deal?
Normally, it's not a big deal. It is estimated that 1 in 1,000 will have a deep vein thrombotic incident or pulmonary embolism in their lifetime. Heterozygous Factor V raises this risk to 5-7 times. Homozygous factor V raises the risk 25-50 times. Still, that's not so bad. 50 out of 1,000 is only 5%. In addition to the an inherited risk (such as the Factor V mutation), you can also acquire risks through smoking, surgery, prolonged periods of immobilization, birth control pills, hormone replacement therapy, and pregnancy (see below).

What's the Big Deal if You're Trying to Get Pregnant?
Well, no one's really sure, but it's possible that thrombophilia interferes with implantation: your uterine lining is so busy clotting that there's no place for the embie to find purchase. However, there's also a study that suggests that the Factor V mutation is actually beneficial to implantation during IVF.

What's the Big Deal if You're Already Pregnant?
There's more agreement about this. Pregnancy exacerbates the problem, which puts you at higher risk for second trimester fetal loss and other fun stuff like pre-eclampsia and placental abruption.

How Do You Treat Factor V?
Typical treatment protocols include baby aspirin and/or heparin.

Who the Hell Are You and What Makes You Think You Know So Much?
This is perhaps the most important question of all. I know nothing. I was recently diagnosed with this mutation, but I'm not a medical professional. If you want to read more, there's a good overview here, but really, the best bet is to talk to your doctor.

Comments

[Anne]

“who the hell are you”

Why you’re the girl with a great hematologist who has a librarian in her back pocket, that’s who! (well and you’re probably also a girl who knows a thing or two about how to use google:))

[Julie]

Posts like this make me weak in the knees I love reading useful information written from the infertile perspective!

[Danae]

Oh crap, now I have something else to obsess about. Thanks for the info. I think I'll go take a baby aspirin right now.

[Heidi]

My brother has Factor V Leiden. He actually discovered it a few years ago when he stayed up all night playing video games and then developed a blood clot in his leg! (Can you believe he stayed up ALL NIGHT playing video games? Believe me. I have made fun of him many times for this. He's actually a normal person too!) Anyway, now he's on heparin, but other than that, everything is just the same as it always was. Good luck to you.

[k]

hey! i've hit your blog a couple of times while searching on fvl stuff. I always enjoy reading about it from your perspective - I often feel the same way, c.f. this post. girl, it's true - if you've gotta have something that makes you lose babies, at least it can be the one that makes it easier for you to get preggo in the first place and keep the kid long enough to start your lmw heparin injections. I'll be back to read more later. good stuff. Take care, k.

[Debe]

I'm a mutant, too and this is one of the best explinations I've seen of Factor V. Thank you

[Windy]

Thank you so much for posting this. I found out this morning that I also have Favctor V Leiden Mutation. I have been worried sick all day about it and reading your post has set me at ease a little bit especially since I'm heterozygous. Thanks again for posting.

[Tammy Ethier]

I have been diagnosed with Factor V leiden mutation (homozygous), so is all my family. Im really worried about having more children. I already have a 3 yrs old boy.I had no complication during and after my pregnancy. Will my little boy have this disorder too????

[Maria]

I just want to thank you for your post and the nice overview you recommended. My husband (42 yrs old) developed a DVT in his right calf last July 3. This past March, after his therapy of Heparin and Coumadin ended, he was diagnosed as having FVL. We were told to get our children tested. We just found out this week (day after my father died - boy is life fun) that our 18 year old daughter also has it, and thank God because she was taking oral contraceptives for heavy bleeding/cramps. So now she's off to college, not happy about having to deal with bleeding/cramps, and I'm not happy she has to have pregnancy risks, surgery risks, HRT risks...but at least she's off the oral contraceptives and her risk is greatly reduced. I don't know if we're going to have our 11 year old son tested now or wait until he's older...too much at once. Thank you again - your blog is wonderful - you seem like a fun person, mom, and cat owner! Maria

[Kari]

Thanks for posting this. Can I ask you when you started on heparin shots during your pregnancy? I have Factor V Leiden and Activated Protein C Resistance. At 28, I had DVT after a long flight to Europe while I was on birth control pills - doctors in France tested me and discovered my blood disorders. Then at 36 I when got pregnant, they found the heartbeat at 6 weeks, started me on Lovenox injections at 7 weeks, and then at 9.5 weeks I woke up and didn't feel pregnant anymore. When the nurse asked me if I was bleeding, and I said no, she said "why don't you wait a few days and see what happens?" I said "so is it normal to wake up one day an no longer fee pregnant then???" She booked me immediately and the high-risk OB told me there was no more heartbeat and the fetus stopped growing at 7.5 weeks. Now that I look back on all of this, I wonder if it had anything to do with having heparin shots so early in the pregnancy. I'd like to start the shots in 2nd trimester, once I manage to get pregnant again. (Trying IUI now, and will try IVF if needed. The first pregnancy was without doctor's assistance.) So when did you start your heparin injections? Did you take baby aspirin while you were trying to conceive? What ended up working for you? IUI or IVF?