QuestionHello, I am 33 weeks pregnant and just diagnosed with Factor V leiden deficiency. I have to get more tests ran to make sure I don't have to be put on Heparin. I heard that women with this blood disorder are more likely to have still born babies. I was wondering what the likeliness of me having a still birth were.
AnswerDear Stephani,
Factor V is a protein in the blood that is required for normal clotting to occur in response to injury. Throughout the course of a normal day, the blood vessels sustain many nicks and scrapes on the inside that we cannot see. The blood coagulation mechanism is therefore activated many times during the day to repair the damage. When this happens, our body reacts in the following way:
- Blood clotting cells (platelets) are drawn to the site of injury on the blood vessel, where they form a loose plug over the leaky area.
- Enzyme reactions occur on the surface of the platelets to generate strands of fibrous material called fibrin. Fibrin acts as a biological "band-aid" to hold the platelets firmly to the injured site and prevent blood from leaking out. This combination of platelets and fibrin is called a clot. Factor V is a helper in the enzyme reactions that form the fibrin in the clot.
- When enough fibrin has been made, a substance called activated protein C (APC) inactivates factor V, helping stop the clot from growing any larger than necessary. The clot then remains in place while other enzymes repair the damaged blood vessel.
Those with factor V Leiden have a mutation in the gene for factor V. Factor V Leiden is an abnormal version of factor V that is resistant to the action of APC. Thus, APC cannot easily stop factor V Leiden from making more fibrin. Once the coagulation process is turned on in people with factor V Leiden, it turns off more slowly than in people with normal factor V.
You may have inherited one copy of the factor V Leiden gene from one parent and one copy of the normal factor V gene from the other parent, making you heterozygous for the factor V Leiden gene mutation. This means that you have about 50% of normal factor V and about 50% of abnormal factor V Leiden in your blood. Sometimes both parents pass factor V Leiden to their offspring, making it possible to have two abnormal genes. If this applies to you, then you are homozygous for factor V Leiden, and 100% of your factor V is the abnormal Leiden variant. Heterozygous factor V Leiden is found in about 5% of the white population and is most common in people of Northern European descent and in some Middle Eastern populations, whereas the homozygous form is found in fewer than 1%.
Factor V Leiden increases the risk of developing a DVT during pregnancy by about 7-fold. They also have an increased risk of preeclampsia, as well as miscarriage and stillbirth due to clotting in the placenta, umbilical cord, and/or the fetus (fetal clotting may depend on whether the baby has inherited the gene). Many of these women go through one or more pregnancies with no difficulties, while others may miscarry over and over again, and still others may develop clots within weeks of becoming pregnant. But most women with factor V Leiden can be treated throughout and have normal pregnancies and only require close follow-up during pregnancy. The treatment for high homocysteine levels is supplementation of vitamins B-6, B-12, and folic acid. Also - standard practice in most cases is prophylactic treatment with low-dose Low Molecular Weight Heparin (LMWH, usually Lovenox) for women who are not actively clotting and therapeutic anticoagulation with LMWH for women with active clotting. Women who exercise regularly and are not immobile for long periods of time will have better circulation and less opportunity for clots to form.
In the May 1999 issue of the Annals of Internal Medicine, Dr. Johan Meinardi reported an increased risk of pregnancy loss in both those who are homozygous or heterozygous carriers of the Factor V Leiden mutation. Fetal loss of any type occurred in 31.6% of carriers (compared with 22.3% of noncarriers). Miscarriage - meaning fetal loss in the first 20 weeks of pregnancy - occurred in 29.4% of carriers (17.4% in noncarriers). Stillbirth - meaning fetal loss after 20 weeks of pregnancy - occurred in 5.7% of carriers (5.0% in noncarriers). Fetal loss recurred in 10.1% of carriers (4.1% in noncarriers). Homozygous carriers had a greater risk for fetal loss and stillbirth than heterozygous carriers.
One cause of pregnancy loss is clotting in the small blood vessels of the placenta. Clotting can occur on either the fetal or the maternal side of the placenta. This makes us question whether the increased risk of placental clotting and fetal loss is based a problem in the mother's blood or the fetus's. The importance of this distinction is increased by the fact that the frequency of the factor V Leiden mutation in miscarried fetuses has been found to be more than twice that in the general population. Thus it appears that the carrier status of the fetus, rather than that of the mother, may be the main consideration in fetal loss.
Also - please be aware of warning signs of deep vein thrombosis (tenderness, swelling, pain that does not subside) and pulmonary embolism (shortness of breath with pain, localized pain that does not subside, a 'bruised' feeling on deep inhale). Both are easily confused with other problems but can be life threatening.
I do apologize for the delay in answering. I suffer from migraines and have had a three day-er since returning from a mini-vacation. I hope this has helped you and answered your question. I wish you well.
Brenda
