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Blood-Clotting Disorders: How They Affect Your Ability to Get Pregnant

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Normally, a small cut on a blood vessel wall causes the body to form a blood clot to seal it and stop the bleeding. However, some people form blood clots too easily. If you tend toward excessive blood clotting or if the clots don’t dissolve properly, you’re said to have a blood-clotting disorder.

Several things can alter the body’s normal blood clotting process. For example, smoking, plaque on the inside of the arteries (atherosclerosis), and birth control pills can increase the risk of excessive blood clots.

Pregnancy can also lead to excessive blood clotting. Since more clotting factors are in a woman’s blood during pregnancy, a pregnant woman is six times more likely to develop blood clots. Also, because the uterus compresses the veins during pregnancy, the blood flow slows down as it moves through the vessels and may lead to blood clots.

What Causes Blood Clotting Disorders?

A blood clotting disorder is a result of the body making either too many blood clotting factors or too few anti-clotting factors that limit clot formation.

Excessive blood clotting may be caused by genetic disorders which are inherited from one or both parents. Two common disorders are “factor V Leiden” and “prothrombin mutations.” They increase the risk of developing a potentially dangerous blood clot which could travel to other parts of the body. They may also cause small blood clots to develop within placenta tissue which could lead to a miscarriage.

Some blood clotting disorders are due to problems in the immune system. Lupus anticoagulants are antibodies that attack those substances that the body normally produces to prevent blood clotting. People with those antibodies have a high risk of blood clotting.

How Do Blood Clotting Disorders Affect Pregnancy?

Genetic and immune clotting disorders are associated with recurrent miscarriage. If you have factor V Leiden and prothrombin mutations, you may also be at risk of having a placental abruption, which happens when the placenta partially or completely separates from the uterine wall before delivery. This results in heavy bleeding which is dangerous for the pregnant woman and the baby.

Factor V Leiden and prothrombin mutations may also increase your risk of other complications during pregnancy, such as pregnancy-induced high blood pressure and slow fetal growth.

Although most women with these mutations have normal pregnancies, it’s important to talk to your doctor about your own risk of abnormal blood clots and pregnancy complications.


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Comments (104)

5 years ago my husband and I were tested for Factor V Leiden - he had two strains and I had one. We questioned our doctor if this could be the reason for (at that time 7 miscarriages) and as of two years ago, 10 miscarriages all around 8-10 weeks. He said no. After the 8th miscarriage and losing an incredible amount of blood and being hospitalized we stopped the fertility treatments. I have two questions: 1.) is this something new that doctors are learning about and 2.) Does this "prevent" you from becoming pregnant? If so, is there anything we can do naturally to increase the pregnancy odds because now we aren't even getting pregnant.

Thanks so much for any assistance!

40 and the clock is ticking!

Hi, I just turned thirty and I have decided that I to finally want to become a mother. But, unfortunatley I have suffered from to DVT's in the same leg. They have put me on 5mg of Warfin for the rest of my days. I have been taken Warfin since July 2008. One doctor asked did I have children and I replied no and she told me that she thinks that it wld be a wise for me to consider having my tubes tied. I was crushed. I have my blood checked once a month and I watch what I eat but I still smoke which I know is not healthy for me. I have begun to slowly quit day by day. I hate needles and I know that I will have to take the injections on a daily basis, I know that the risks are high but I am willing to take the risk. I just want a baby if only just one. I just wld like to know what are the steps that I need to take to maintain a helthy pregnancy. And what types of specialist that I need to see since I have been having a hard time concieving. Do I need to get tested for APS?

im 26, i have factor II mutation, leindens mutation and MTHFR. i had a son 8 yrs ago and i have had ten miscarriages after him. i recently had a miscarriage and i was taking heprin, folic acid, prenatals, iron supplement, baby asprin, metaformin. i just wanted to know if i will ever carry another child.

I'm currently 31 with MTHFR, prone to blood clots, and RH negative. I've had 3 miscarriages, complete molar pregnancy, a still born, and a ruptured ectopic pregnancy. I have an 8 year old son and now a 1 year old baby girl. Their age gap was not by choice! I want to tell you NOT TO GIVE UP! I know it's frustrating, heart breaking and beyond difficult, but just know that it's not impossible.

I am so very sorry for your losses. Anyone who has suffered multiple miscarriages should be seeing a fertility doctor rather than an ob/gyn. A fertility doctor can help assess your particular situation and answer your questions. I can't give you medical advise, but I do encourage you to work with a fertility doctor - you can search for one on this website. Also, you may want to visit, which is a very active online community - where you can connect with other women in similar situations.

I just found out I might have blood clotting disorder.I have been pregnant 4 times and each of my pregnancy's have ended in miscarriages.Since my last pregnancy in 2003 I have not been able to conceive.What can I do to finally get pregnant and have a healthy full term pregnancy?

I was diagnosed with 3 clotting disorders 4yrs ago (Factor V Leiden, MTHFR and Protein S deficeincy). Im 31 and luckily have never had any clots. A few golf ball sized hematomas but luckily nothing worse. Ive recently been trying to get pregnant and unfortunately had my 1st miscarriage in May of this year. Ive been wanting to start to try again. I saw my hematologist this week and he told me to get the idea of having children out of my head. That its way risky. I was horrified. Im still severly depressed from the miscarriage and now he tells me that I shouldnt even try anymore. Im so lost.

I have a normal pregnancy at age 15 my son is 7 yrs old now and i found out that i have a cloting problem when i was 19 yrs old . I have had a miscarage and i got pregnant again a yr after that and i had a little girl i dilievered her at 29 wks she only lived 6 days . I want to have another baby . my high risk doctor say that i can have more kids and that i would just have to be on lovenax and a baby asprin everyday while im pregnant and be monitor closely. I just dont no what to do because a regular doctor that i seen said that i shouldn't have anymore kids cause of my cloting problem but hes not a high risk doctore either that deal with girls like me. i don't want nothing to happen to me so i just don't no what to do . Is he save to have another baby ? I just don't want to have to put another child in the grown either but i really do want another child to i dont have a baby with my husband now and he dont have any kids we just have my son from my last boyfriend when i was young . please help me out ..

I have had two d & Cs in the last year because of absent miscarriages. My fertility doctor can't find anything that she thinks could cause them. I have two children of the ages 3 and 6. They were healthy pregnancies, except for high blood pressure with my oldest. My uterus is healthy, my hormone levels are fine and we are not having any problems getting pregnant. She has put me on baby aspirin daily to help with any clotting disorder that may be occuring. Is this normal? She hasn't tested my blood for clotting! Is she just stretching for something to help with the miscarriages?

I have had 2 miscarriages this year (May, October), both around 5 weeks. I took a tissue sample in to the doctor and am still awaiting any news. But she did see me 2 days after my recent miscarriage, told me that it could be blood issue. So, she has me coming back in 3 months to have my blood tested. Told me to wait a month or 2 before trying again. Is there a reason why she would wait 3 months to do a blood test? If there is a reason or not, why would I be able to try again in a month or 2 before having the blood test done?

How do I get tested for a blood clotting disorder? I've had 5 miscarriages; my mother had blood clotting issues, so I am wondering if it has something to do with miscarriages. Do I need to be pregnant to get tested? What is the name of the test? And does one test cover all blood clotting disorders?


I have Mthfr C677T, i've had two losses(19wks,and 12wks). I'm currently pregnant again @ 5 wks. My dr has me on 40mg lovenox injection, 81mg aspirin, 5mg folic acid, 1 Néevo prenatal, 1mg b12, 100mg b6, 2 omega 3,6&9+DHA. Am I taking enough lovenox? I also have anti-nuclear antibodies and RH incompatiblity. Is there anything else I should be doing? Any advice will help I'm very scared I'm not doing enough.

Hi my name is ashley and i'm 4 weeks pregnant. And I'm starting to get some pains on my side and below my belly button. I don't have a doctor yet. And I'm worried what do i do? I also had a miscarriage 5 yeats ago.

Hi Ashley - If you are having any concerns, please call a doctor in your area - an ob/gyn or a primary care physician. Or if you think it's an emergency go to the emergency room at your nearest hospital or call 911.


hi. i had 2 stillbirths and 1 baby that died 2 days after birth. i was takin the heperin shot at 5 months and i developed a hemotoma and the doctor stopped giving it to me and i ended up passing a large blood clot while i was hospitalized for high blood pressure. i had low blood platlet count. i was only 26 weeks this last time when i had to have an emergency c-section. my doctor told me i have a blood clotting disorder but dont know which one i have. i need some advice. im thinking about getting my tubes tied but i really want another baby. i have 1 that is 5 years old and with that pregnancy i had no problems besides premature labor. how could i have one than end up having problems with my other pregnancys?

WHAT SHOULD SHE DO SHE IS 18 yrs. of age and just starting college.

I am so sorry to hear of everyones lost. I do have three children and my husband want to have one more, but with my last baby I developed blood clots in my legs and was hospitalized from five days. I want another one but are the risk very high when u havve had pervious DVT's?

I am 40 years old, have 2 children aged 10 and 7, but always planned for a third child. In the last 4 years I have had 6 confirmed miscarriages, mostly at around 7 weeks, but the last one at 10 weeks. However I'm sure I've had several other miscarriages during this time, at 6-8 weeks gestation, but had not taken pregnancy test so GP doesn't record it as such. In every pregnancy except the first, including my 2nd live child, I've had light daily bleeding in first trimester. The last miscarriage, at 10 weeks, was truly awful. Lost huge amount of blood with many large clots (the size of squashed apples), was hospitalized and given a transfusion. Bled heavily for 4 weeks, finally stopped bleeding after 6 weeks. My iron level dropped to less than 3 and have been on 630mg iron p/day for 3 months since - iron level now at 13 so nearly back to normal. Have been referred to miscarriage clinic, who took little interest in my case, due to my 2 live children, but recommended I take low dose aspirin and progesterone every day 'next time I fall pregnant'. I know this is normal treatment for blood clotting disorder, but is it normal to take this action without any testing first. And are my symptoms of light daily bleeding in first trimester normal indicator of this type of disorder? I'm terrified of trying again without any investigation of what is causing the miscarriages, but I would desperately love to have a third child before it's too late for me.

you cant take progesterone while your pregnant with a clotting disorder. I found that out. I have a blood clot on my brain now due to taking the HRT pills and not knowing something was wrong with my blood. But you can never take HRT pills again once your diagnosed with a clotting disorder. I am highly upset because I have lost 2 in the last 7 months. I am on blood thinners for the clot and if I get pregnant again I pray the lord will let me have a full term pregnancy I cant take the emotional toll of loosing another,,,

I'm so sorry that you've been going through this. You should definately see a fertility doctor - reproductive endocrinologist - and if there's one in your area with expertise in miscarriage/repeat pregnancy loss, even better. On the top right of every page on FertilityAuthority there's a Find a Clinic/Find a Doctor search. Type in your zip code to find a doctor in your area. It's important that you see a fertility doctor sooner rather than later. S/he can help diagnose miscarriage issues and guide you toward the right treatment. Best of luck.

My granddaughter is taking heparin 2 times a day. She is 37 weeks pregnant. She had a lot of bleeding early in her preg. She had a "bleed" that was caught on sonogram. She was diagnosed with a clotting disorder. Before the heparin shots, she was getting Lovenox once a day. I am not sure why we had to switch to heparin shots. No one was monitoring her blood so we saw a hematologist who said all was well. Tomorrow she sees her OB/GYN to get more genetic testing and to answer some questions. As long as she is monitored, she feels safe. She has not had any bad symptoms from the Lovenox or heparin.

I have a clotting problem too did her doctor say that she can have more kids or not since she has a clotting problem My high risk doctor said that i can have more kids but my doctor thats dont deal with high risk says that i shouldn't have more kids. So I really dont no what to do I have a 7 yr old and i had one miscarriage and then i had my little girl and she passed away 6 days after she was born she was premmie so i dont really no what to do . i want to have another kid so who should I listen to.
Thanks D

i have had 5 miscarriges in 5 years they just found out that i have a clotting disorder....i was just wondering if there is anyone out there with any advice about taking blood thinners while your pregnant? and does it really help you not to miscarry? and does somking really have a part in it at all?

Excellent blog. I would like to read more on it. This is serious issue which cannot be neglected if you r planning for pregnancy. well do you know about flexeril. Do they have any side effects if taken in pregnancy. Please advise. Thank you.

I have been diagnosed with the Factor II and Factor V mutations, both which cause excess blood clotting. I have been told that once I become pregnant I will need to inject lovenox twice daily. Does anyone know how long this has been used/tested? I'm worried about longterm effects for me and/or my baby. Is it safe?

I have had 2 miscarriages in 3 years but was never told about blood clotting the first pregnancy I was 8 weeks the second pregnancy I was 7 weeks then I miscarried my doctor never mentioned anything about blood clots and told me it's becuase the baby would have been abnormal. After my second miscarriage he told me that if I have a third miscarriage then only do they run tests to see what the problem is I have been trying now for the past 8 years to have a baby but with no luck I am so depressed and I have such terrible mood swings I changed my doctor and I am now hoping for the best because my first doctor told me maybe I need to loose weight to fall pregnant.

i hae a 2yrold little girl that is healthy,but i hae lost 2 babys in the last two yrs and it turned out that i hae a blood cloting disorder,my doctor told me i would hae to take shots when i get pregnant,well im finally preg again which we tried and tried for a 1 yr and the same thing last time. i called my doctor to tell him and to get put on the shots right away,he told me no that he needs to see a heartbeat first,well i lost both babys at 6-8 weeks so how will my baby lie if my doctor woulnt give me what i need to keep it alive??? i want this baby sooooooo bad,it hurts. im on baby asprin and folic acid and hae been for about a yr. what do i do?

I have two blood clotting disorders, Anti Phospholipid Syndrome and prothrombin disorder. One is definitely genetic and have passed them to both daughters who are trying to have children. Alot has changed since I gave birth to them. FIND A HEMOTOLOGIST FIRST! Get tested, find out what is up with your blood. THEN, find a GYN who will work with your blood doctor. GYN's seem to want to wait, but that is not necessary in most cases. Twenty years ago, standard practice allowed at least two miscarriages before testing. New blood testing procedures have changed that practice. GOOD LUCK!
One of my daughters is giving herself Heparin injections daily now. She is only 8 weeks pregnant and is doing very well. She began shots three weeks ago and was on daily baby aspirin before getting pregnant. The other daughter takes Prometrium and daily baby aspirin.
BTW, I have four children and had four pregnancies. I didn't start having clotting complications until the last child. Had a huge DVT after he was born. Hemotologists believe your age, (all my kids born before I was 27)hormone levels, have an impact. Clotting problems are LIFELONG and end up affecting lots more than childbearing.

Hi i would find another doc because i have a cloting disorder i i found out about after i had my first child then i started take n birthcontral got a clot found out it was for the Birthcontrol and i got the gen from my dad cuz he had them but i got preg lost it at 2 mons cuz my body was not ready... I was on 12mg of wafan one n 15mg of wafran the next day i found out at 5 weeks i was pregnant so the day i found out i called am Ob and he got me n soon i am now 7 mons pregnant and on 100mg of lovenox n the morning and 100mg at night and my pregnantcy is going find so find another doc ASAP..Trust in him and trust in god all will work out in time yes it hurts but al will work out in time..God Bless u..

Find a new DR! I started my Heparin injections AS SOON as I found out I was pregnant. At 6 weeks! It has kept me from having any miscarriage and I am now 6 months! As I said above research, Vitamin K and Potassium intake in your diet too! This causes clotting and even if you are on injections it will counteract it. Find a high risk specialist ASAP!!!!!!

I have had 5 losses in less than 4 years and found out that I have a blood clotting disorder and have to take daily injections every time I get pregnant .I don't want t go through this again. I have a 4 year old son that is very healthy. I can't put another child in the ground, and I don't know what to do.

I know what you mean! I had 4 miscarriages before I had my son. I had to take injections the entire time I was pregnant with my son 2 times a day high dose of heparine. My son is now 5. I long to have another child, but know that if I become pregnant again, I would have to do the same treatment(the shots). I love my son dearly. the only thing I can say is enjoy every minute with your son. If it is meant for you to have another child, things will work out for all. I would repeat the shots all over if it meant having another child & carrying full term!!!!

i am 31yrs old and have blood clot issues. I can remember having this problem as far back as fifteen years. I started getting the pepo shot a year prior to loosing my verginity. I have been trying to get pregnant for over a year and need advise on the right steps to take. From my symptoms, i believe i might have polyps but not sure.

I have had 2 miscarriages and have no children. I had DVT in my right arm and multiple pulmonary embolisms in 2008 and i had 2 DVT's in 2009 in my right leg and groin area. I have been tested for every disease, disorder or illness and everything came back negative. But why then, do i keep having miscarriages and keep getting blood clots??? I have been to many speacialists but they don't have any answers. I am confused and frustrated. I am taking warfarin for the last 2 years and now have to stay on it for life - doctor's orders. thats all they could say to me. Can anyone help me?

If you've had multiple clotting incidents and all tests are coming back negative, ask to be tested for Antiphospholipid Antibody Syndrome (APS). I live in Los Angeles and had my first PE at age 26 and was completely healthy otherwise (normal weight, good activity levels, etc). After 3 years and 4 doctors, I kept demanding that someone better find something they could show me in a lab test to prove there was something wrong with me, otherwise I did not want to take Coumadin anymore. Finally a specialized hematologist I found was able to find the answer. Since then, my brother has also experienced DVT and a heart attack, and sure enough he has tested positive for APS as well. My father has also had multiple PEs. They say it's "acquired" but there's definitely some genetic factor here. This tends to be a newer syndrome whereas older hematologists I saw hadn't heard of it nor did they know how to test for it. I recommend looking into this b/c one of the main ways it presents itself is by multiple miscarriages. If it helps at all though, I had a completely normal pregnancy and healthy baby in spite of it and have never had a miscarriage. So don't get discouraged.

I'm 24 years old and am ttc. We have been trying for almost a year and have had 2 mc. My gyn told me his wife had 4 mc then had a healthy child so I should not worry about it. I don't consider that advice helpful. I don't know what is going wrong. I always have low body temperature and heavy periods with lots of clots. Are there any tests I should request from another gyn or should I just keep trying without treatment? Please help because I don't know what to do and am having a hard time with it.
Thank you

Anonymous 29,

I'm sorry to hear about your losses. I would consider finding another gyn who is more understanding. The first thing that comes to mind with low body temp. is a thyroid problem. Have you been tested for that before? I would also get tested for the clotting disorder. I too have had 2 mc and it's so helpful to have a midwife who cares and is supportive. Maybe try a midwife or another gyn.

I think my daughter has this clotting problem with pregnancy. Her father does have some auto immune problems so it could be. Her GYM is testing her for it. Can you give me more information. The gyn is also talking Lovenox injections with the next pregnancy and I am very scared of her taking them. HELP.

Oak Tree, just wanted you to know that I got your email and I'm going to answer you off the boards!
Need help with our site? Contact me at I'm happy to help!

I have had 5 miscarriages in three years. My specialist told me that I have blood clotting issues. I was told that I can resolve this by taking injections of lovenox daily during my pregnancy. Is there something else I could do before I become pregnant and during my pregnancy? Please help, I want to have children but I am afraid of getting pregnant again.

Hi, I lost a baby at 34 weeks pregnant. They told me I had two gene mutations that cause me to clot more. I was on Lovenox my last pregnancy, a baby asprin and b12. I had a great pregnancy, no problems. The lovenox sucks and hurts a bit, but it does not do anything to the baby. Plus the delivered by baby 3 1/2 weeks early because of the condition. I am sorry for your losses, its the hardest thing in the entire world. But lovenox might help

I lost a son at 20 weeks due to which my doctor believed to be a blood-clotting disorder, specifically because of MTHFR gene. I became pregnant three months later and took daily shots of Lovenox throughout the pregnancy. I gave birth July 09 to a healthy baby girl. I do not take any medication now. You can do it and the shots get better. The results are worth it in the end.

Hi my name is angela i am 24 years old i had one pregnantcy that went fine than i got a clot that out me n the Hospital they found out i have cloting disorder than i got pregnant and lost it a 2 mons.. I am now 7 mons pregnant i am on Lovenox Twic a day 100mg n the am n 100Mg n pm my pregnantcy is going good the Lovenox injections are not fun at all but if u want to have kids this this the only way u can.. Trust in ur doc an trust in God if he said u need to be on Lovenox during ur pregnantcy than do it..

5 miscarriage is a lot in life. Blood clotting issue is really a bad thing but taking injection of lovenox daily is also a good solution. If the specialist has said so than I prefer you to take the injection when you get pregnant.All you can do is make some good and positive hopes and all will be fine sooner.

I am 6 months pregnant now, I do have SEVERE clotting issues (had a heart attack in 05 relating) and since the beginning of my pregnancy I have been taking 5000unit injections twice a day of Heparin. It does not cross the placenta so it is safe for you and the baby. I have had a healthy pregnancy so far. I go to the Dr every two weeks where they continue to test my blood to make sure its not clotting and we have a specific birthing plan around delivery. I particularly watch my diet, Vitamin K increases clotting factors which is in EVERY green leafy veggie (spinach, broccoli, asparagus) and a lot of other foods you would not expect like mashed potatoes, kiwi, spaghetti sauce (GOOGLE IT!! Its crazy the restricitons) ...look into how much VITAMIN K and POTASSIUM you are taking in on a daily basis BEFORE AND DURING your pregnancy. Pregnancies can be somewhat normal with clotting factors.

I understand fully & completely what you are going through!!! i had to do the same thing. I suffered 4 miscarriages until my doctor sent me to a specialist. they found through blood work that I had a severe clotting disorder which only affected me during pregnancy. I took heparine shots 2 times a day(about the same amount as you). My child is now 5. the bad news is if I were to get pregnant again, I would have to have the same treatment.(heparine shots 2 times a day). Good luck & best wishes to you, your family & your baby!!!!

I am so sorry for your losses. Are you feeling uncomfortable with your doctor's recommendation of Lovenox?

Need help or have a question? Contact me!

if i was to take asprin verses warfrin for factor 5 disorder how much asprin would i need to take to equal 5mg?


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