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How Vitamin B12 Affects Fertility

Here’s how vitamin B12 affects fertility, plus tips for getting more vitamin B12 in your diet so you can get pregnant. And, a new test for B12 vitamin deficiency. Both male and female fertility can be seriously affected by something as simple as a vitamin B12 deficiency.

Vitamin B12 for FertilityIf you don’t think you’re getting enough vitamin B12, think about getting Methyl B-12 Vitamins that support brain cells. Why? Because “Vitamin B12 deficiency is associated with infertility,” says hematologist Michael Bennett, M.D. in Could it be B12? “Pregnancy may occur in the presence of B12 deficiency but may be associated with recurrent early fetal loss.”

Plus, a deficiency of B12 leads to reduced sperm counts and sperm motility. To learn more about the effects of this vitamin on fertility rates, read Could It Be B12? An Epidemic of Misdiagnoses.

Below is how vitamin B12 deficiency contributes to infertility – and what you can eat to increase vitamin B12 in your diet. This book also discusses how a vitamin B12 deficiency affects heart disease, autism, and other medical conditions.

Fertility and B12 Vitamins

“Doctors have reported successful pregnancies in once-infertile women following therapy for B12 deficiency,” write Pacholok and Stuart in Could it be B12? “Yet often, sadly, this deficiency is overlooked even by infertility specialists until women have undergone months or even years of unsuccessful treatment. As a result, many couples spend thousands of dollars and suffer disappointment after disappointment, when treatment with B1 injections might have solved their problem.”

How vitamin B12 affects fertility

These authors say researchers don’t know exactly why a vitamin B12 deficiency makes it difficult to get pregnant and carry the baby to term. The deficiency could interfere with ovulation or normal cell division – and even affect how the fertilized ovum is implanted in the uterine lining.

Whatever the exact link is between vitamin B12 deficiency and female or male infertility, these authors say that a B12 test may improve the chances of getting pregnant naturally. Also — it may be wise to avoid certain foods when you’re trying to conceive a baby.

Foods High in Vitamin B12 (from highest to lowest)

  • Mollusks, clams, cooked
  • Liver, beef, braised
  • Fortified breakfast cereals
  • Trout, rainbow, wild, cooked
  • Salmon, sockeye, cooked
  • Trout, rainbow, farmed, cooked
  • Beef, top sirloin, lean, cooked
  • Cheeseburger, double patty
  • Yogurt, plain, skim
  • Haddock, cooked
  • Clams, breaded, fried
  • Tuna, white, canned
  • Milk
  • Pork, cured, ham, lean only
  • Egg, hard boiled
  • American pasteurized cheese
  • Chicken breast, roasted

If you’re worried about vitamin B12 and fertility, read 13 Tips for Getting Pregnant Without Taking Fertility Drugs.

Eat Foods High in Vitamin B12 to Get Pregnant

Vitamin B12 doesn’t just help you get pregnant, it affects your developing baby! “Insufficent B12 in the developing infant is linked to serious and potentially fatal problems, including neural tube defects and neurological abnormalities that can lead to mental retardation or autism,” write Pacholok and Stuart in Could it be B12?.

Don’t let this alarm you – it’s easy to get enough vitamin B12 if you eat a healthy, balanced diet. Just pay attention to the B12 levels in your food; if you’re not getting enough, consider taking a vitamin B12 supplement. And you might want to read about the 12 Most Common Causes of Fertility Problems.

A New Way to Dectect Vitamin B12 Deficiency

Researchers have developed a new test to detect the levels of vitamin B12 using your breath, allowing for a cheaper, faster, and simpler diagnosis that could help to avoid the potentially fatal symptoms of B12 deficiency. In a study published today, 23 June 2011, in IOP Publishing’s Journal of Breath Research, researchers have developed a simple, non-invasive, low-cost breath test to more accurately measure vitamin B12.

vitamin b12 affects fertility

vitamin B12 and fertility

Vitamin B12 deficiency is a growing public health problem in which the most common tests – using blood serum levels – are limited in accuracy and sensitivity and are non-specific for vitamin B12. Vitamin B12 plays a crucial role in the functioning of the brain and nervous system whilst also being essential for the formation of red blood cells; however in low levels it can cause fatigue, clinical depression and memory loss as well as more detrimental and irreversible effects on the brain and nervous system. Several reports have also linked B12 deficiency to pernicious anaemia and Alzheimer’s disease.

Vitamin B12 deficiency can often be asymptomatic, which means you may not know you are deficient. If you don’t know you’re deficient, you won’t know how vitamin B12 affects your fertility. This accentuates the need for a more accurate and reliable test. The initial testing of the B12 breath test conducted measurements on subjects with chronic pancreatitis, Crohn’s disease, and small intestinal bacterial overgrowth, as well as patients over 65 – all of which are associated with a higher incidence of vitamin B12 deficiency. After fasting and not smoking for 8 hours, the study subjects were orally administered 50 mg of propionate and then tested every 10 minutes for the first hour and every 15 minutes for the second hour, with the best diagnostic accuracy appearing to be the 10 and 20 minute intervals.

To ascertain the accuracy of the breath test, the obtained vitamin B12 levels were compared with several blood compounds that are currently used to ascertain vitamin B12 deficiency. The authors concluded that the results from their study indicate that the vitamin B12 breath test is a non-invasive, sensitive, specific, and reproducible diagnostic test to detect vitamin B12 deficiency.

For more tips on vitamin B12, fertility, and getting pregnant, read Fertility Diet – 5 Delicious, Vitamin Rich Foods for Fertility.

If you have any thoughts on vitamin B12 and fertility, please comment below. I can’t offer medical advice on vitamin B12 and fertility, but I can listen to your story…

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32 thoughts on “How Vitamin B12 Affects Fertility”

  1. Hi Laurie

    I am wondering if the B12 Vitamin is very important to good health. I feel tired, tired and have some pain in my body that made me test my levels of b12. I scored 333 is this good or low level?


  2. Vitamin B12 isn’t just for fertility – a new study found that Vitamin B12 levels in the brain are significantly decreased in the elderly and are much lower in individuals with autism or schizophrenia, as compared to their peers at similar ages. For example, children with autism under the age of 10 were found to have three times lower brain B12 levels, which is similar to levels for generally healthy adults in their 50s, indicating a premature decrease.

    And, older people with low blood levels of vitamin B12 markers may be more likely to have lower brain volumes and have problems with their thinking skills, according to researchers at Rush University Medical Center.

  3. I recently heard about a new oral prescription alternative to the injections called Eligen B12. I recently read that it works even if you don’t have intrinsic factor (so even if you don’t have normal gut absorption). Apparently it came out a month or two ago. Has anyone heard of it or tried it??

  4. If you’re thinking about vitamin b12, talk to your doctor! I don’t know how much you should take or how often, but I have heard that vitamin b12 can help with infertility and getting pregnant.

    But it depends on the woman, which is why it’s really important to talk to your doctor.


  6. how much b12 do you need to take to get pregnant as a friend bought some here in the uk for me but they are 1000 mcg each lozenge does this sound too high, i am 44 and have been trying for years to get pregnant again with my new husband but feel like im running out of time im 45 this christmas and would love to give him the perfect christmas present

  7. My husband and I have been trying to concieve for almost a year now. I start seeing a gyn a year ago and he kept giving me fertility meds which werent doing the trick, well i went for months just not even thinking about getting pregnant and started having anxiety real bad so i went to my family doctor. She put me on anxiety meds and did blood test to see what could be causing me to have such anxiety well 2 days later she called me and said that everything came back normal except my b12 was extremely low, and that i need to get on b12 tabs real quick, so i got on them i felts alot better and something in the back of my mind when i was looking at the bottle and notice energy on it and my mind went to fertility so i looked it up and walla found b12 can cause infertility and since i have been taking b12 i have been ovulating like crazy, so me and my husband are going to try again.

  8. Hi Laurie
    Your articles and advice has been very inspirational – ever since I started to develop mouth ulcers, had hair loss and generally feeling “out of sorts” I found out I was deficient in the B vitamin group, and began a course of medication and did a complete diet overhaul; two months in, and I am feeling so much better! The ulcers have gone, my hair is a lot thicker and I feel that my health has improved overall. Following a miscarriage 2 1/2 years ago I am hoping to get pregnant again soon, and your advice and articles are pushing my dream towards a reality. Keep up the good work Laurie, will be spreading the word about your great site X

  9. Thanks for your comments and insights about vitamin b12 and fertility – I appreciate them!

    Good luck with your Facebook and G+ pages, Richard. It is strange that your vitamin b12 deficiency was just detected…but then again, some doctors say that it’s not one of those vitamins that’s tested for.

  10. I started a group on Facebook and I’m also posting much of the same information on Google +.

    If you Facebook, my group is B12 The New Wonder ‘Drug’, it is an open group.

    I have found so many good things about B12, since I found through blood work, that I was deficient.

    It seems, without any real proof, that I have been deficient for the better part of 20 or 30 years. Strange that it was just detected.

  11. I have just learned I have a B12 deficiency. For some reason I can’t absorb the vitamin from food or pill. But you can get the shots without a perscription in Canada. Just ask for it at the pharmacy. A 10 mnth supply with needles for a little over $10. Might be something to look into if you are not getting enough through other means.

  12. Thanks for your comment, Lovelyn, and for your happy news!

    Readers — before you take any fertility product, make sure you check with your doctor first. There are a lot of scams out there, and natural products aren’t regulated by the FDA or any organization.

    The best way to get vitamin B12 and improve your fertility is to talk to your doctor, or a naturopathic physician. But not just any old doctor! Find one you trust, who has helped other couples get pregnant.

  13. Hello,

    I’m glad you brought up these points. It’s so true! My heart goes out to all of you that are in this situation. For all of you who are TTC, here’s a story for you. My husband and I tried to have children for over 3 years. We were contemplating IVF and adoption, but just trying to save up the money for either was an obstacle. Finally, a family member told us about a product called BeeFertile. It’s a natural fertility product. It’s a 2 part kit and has Royal Jelly in it, which is supposed to be really good for increasing fertility. We were skeptical, but decided to try it. It was so much cheaper than having to take fertility testing, etc. So they tell you that it takes 3-6 months for it to work. I’m happy to report that only after 3 months of taking the kit, my hubby and I got a PPT!!! I am due in September!!! For what it’s worth, I try to tell as many people as possible, because we didn’t think we could ever conceive on our own. Now we know we can.

  14. Hello Sissy,

    I’m sorry to hear it’s taking so long for you to get pregnant! I know how frustrating it is.

    If you want to try vitamin b12 to get pregnant, I encourage you to talk to a doctor first. It’s really important to get medical advice before you try different things — even “natural” vitamins or herbal supplements.

    Have you talked to a gynecologist yet, or a family doctor? There may be health reasons that are causing you not to get pregnant, and the sooner investigate those, the better off you’ll be.

    Talk to a doctor, and let me know how it goes!

    Best wishes,

  15. Hello,

    I have been trying to get pregnant for a long time now. all my friends been telling me about B12 and I was thinking about getting it a try. What should I do???? Please help and need advice on this.. I don;t want to to this an have a miscarrage also.. I desperate want a baby so BAD. I’m getting older an I just want to have a baby.. PLEASE HELP ME

  16. I started b12 injections once to twice weekly about 6 months ago. My fiance and I conceived the first time we were together and am now 12 weeks pregnant and have continued my injections. Before my injections I had never used any kind of contraceptive and never got pregnant. I had no idea I may have been infertile and assumed I could continue to go without contraceptives.. I was wrong! This is in no way conclusive but the connection is undeniable.

  17. Hi,
    After the birth of my daughter who is now 20 months old, I started to become very unwell, anyway after nearly 2 years and 3 miscarriages and no help from the doctors apart from them trying to give me anti-depressants (which I did not take) I did a free on-line health test at Patrick Holford.com. It came back with suspected B12 deficiency. I got tested, my result came back at 66ng!!!!!! I asked the Doctor if this was related to my miscarriage he said NO. I got referred to a Hemotologist who said absolutley YES this was related. I had my first injection yesterday and will now have one every other day for 2 weeks and then get re-tested whilst the hemotologist looks into the causes of this… How long should I wait before trying for another baby?

  18. Laurie Pawlik-Kienlen

    Hi Candy,

    I’m sorry to hear about your miscarriages, and your current folate level.

    Though I can’t advise you about trying to get pregnant, I do encourage you to do two things: 1) talk to your doctor about why he isn’t taking further action; and 2) get a second opinion from a fertility specialist.

    Also, I suggest doing some research on how to decrease your folate levels. Does it happen naturally, or should you avoid certain foods? I don’t know, but I think it’s important to get a doctor’s input. Don’t trust the internet alone.

    I hope you get pregnant soon — I bet you’ll be the happy mother of two kids in a year!


  19. Hi Laurie

    I have posted on this forum before, after having 2 miscarriages last year my dr did some blood tests, he found my b12 to be very low at 226 when the range should have been between 211 and 911. 4 months later i have been retested and now the level is 566. Also he checked my folate level which is 16.8 and the range should be between 2 and 11.5 – my dr said this is abnormal but he isn’t taking any further action. Please can you advise if these levels sound ok for me to try for a baby again? My last miscarriage was 6 months ago and I am hoping i have more chance of carrying a baby to term next time. I have 1 child, 2 years old already.

    Please advise, Candy.

  20. Laurie Pawlik-Kienlen

    Hi Tisha,

    I’m so sorry to hear about your miscarriage. That’s heartbreaking, and I hope you’re doing well these days.

    Regarding how much vitamin B12 you should be taking, the Mayo Clinic says:

    A day’s supply of vitamin B12 can be obtained by eating 1 chicken breast plus 1 hard-boiled egg plus 1 cup plain low-fat yogurt, or 1 cup milk plus 1 cup raisin bran.

    The National Institute of Health recommends that women 14 years and older take 2.4 mcg of vitamin B12 daily, and that pregnant women take 2.6 mcg. Here’s the link to their fact sheet:

    Dietary Supplement Fact Sheet: Vitamin B12

    I wish you all the best in your next pregnancy!

    Take care,

  21. I have tried to get pregnant , last year i was taking B 12 supplement and I got pregnant only to have a miscarriage at 11 weeks. How many mg should I be taking ?

  22. Kristen Burris, L.Ac., M.S.T.O.M.

    The short answer is “Yes” vitamin B12 Deficiency can be a contributing factor in miscarriage.

    Infertility caused by a vitamin B12 deficiency may be related to anovulation, abnormal cell division in the fertilized ovum or a lack of implantation due to megaloblastoid changes in the endometrium. Recurrent miscarriage may also be associated with vitamin B12 deficiency, though it is rare. However, when you are talking about you, rarity or not B-12 can be an issue.
    Recommended dose for B-12 vitamin for pregnant women is 8-10mg daily (or it may read 120 mcg). Here is evidence from the respected Journal of Reproductive Medicine that B-12 may be a contributing factor in miscarriage: “The obstetrics histories of 14 patients presenting With 15 episodes of vitamin B12 deficiency were analyzed. Infertility of two to eight years had been present in four episodes, and recurrent fetal loss was a feature in 11. Two of these 11 cases had never had a full-term delivery. Case 1 had had seven spontaneous abortions before the finding of vitamin B12 deficiency. Treatment with B12 resulted in their first full-term delivery within nine months followed by two more full term deliveries. In six cases, miscarriages were followed by a period of infertility. In one case, after 3 miscarriages followed by six years of infertility, severe megaloblastic anemia was found with ahemoglobin of 5.8 g/dL and a serum B12 level of [less than] 50 pg/mL. Following parenteral B12 administration, the patient became pregnant immediately and delivered a full-term infant. In 10 patients, a full-term delivery occurred after vitamin B12 therapy. Six of them almost immediately conceived. Recurrent fetal loss in the presence of B12 deficiency may be due to elevated homocysteine levels and a resulting thrombophilic state. Pregnancy is already a prethrombotic state, and the homocysteinemia and increased risk of thrombovascular disease may cause thrombosis and inadequate perfusion of the placenta, preeclampsia, abruptio placentae, fetal growth retardation and stillbirth.
    This study demonstrates the importance of measuring B12 levels in the evaluation of infertility or recurrent spontaneous abortions. Since folate therapy, high-folate diets, iron deficiency or thalassemia minor may mask a B12 deficiency, serum measurements are crucial.”
    Bennett M. Vitamin B12 deficiency, infertility and recurrent fetal loss. J Reprod Med 2001; 46:209-212
    B-12 is found in animal products but can be very difficult for a vegetarian to obtain through diet alone. Foods to eat: meat, animal protein, mushrooms, parsley, and turnips. We recommend Metagenics Wellness Essentials for Pregnancy to obtain a pharmaceutical grade vitamin with a high absorptions rate. You can order this off of our website by clicking on my name. Poor digestion can also inhibit the absorption of B-12 so if you suspect your digestion is weak i.e.: belching, gas, loose stool, irregular stool I would also recommend Ultra Flora Plus to improve your digestion. Some patients who show signs of B-12 deficiency including: weakness, fatigue, lethargy, diarrhea, depression, indigestion, paleness or pale tongue, poor memory, moodiness, personality changes or paranoia may want to consider getting supplemental B-12 shots from their doctor.

    Written By: Kristen Burris, L.Ac., M.S.T.O.M., Dip. Ac., a nationally recognized expert in women’s health and infertility treating patients with acupuncture, herbal medicine, vitamin therapy and nutrition as medicine. She is the founder and medical director of American Acupuncture Center located in Eagle, Idaho.

  23. Just to add on to my previous comment – alot of people (including my midwife) have said that I may be miscarrying because I cannot carry boys? Could there be any truth in this?

  24. I have a beautiful 22 month old daughter, but I have suffered 2 missed miscarriages in 5 months – first one I bled at 12 weeks baby had been dead since around 10 weeks and second one baby stopped growing at 6 weeks and found out at 8 week scan. This was obviously devastating. I went to see my doctor who did blood tests and found my iron and B12 are abnormally low, I am now on iron tablets and taking B12 supplements – I’m putting this bad year behind me and I will try to conceive again next year when my body is ready both physically and mentally. I came across the B12 and miscarriage link by chance and I’m so glad I did. Thank you.

  25. Hi Lori (great name :-)),

    I’m glad the vitamin B12 shots are working to regulate your periods…please do update me on whether you get pregnant! My fingers and toes are crossed for you…


  26. This is great information! I have been getting b12 injections every 2 weeks for the past 3 months. I have also had a period for the last 3 months before the b12 I would go 5-7 months without a cycle.

  27. Hi Tara,

    I just wrote another article about how vitamin B12 affects fertility levels, pregnancy rates, and the risk of miscarriage. Here’s the link:

    Let me know if you have further questions!


  28. I have a B12 deficiency and had no idea that it affected fertility. More information about this would be fantastic. Thank youso much.

  29. Good luck with the vitamin B12 and getting pregnant!

    And, I’m sorry about your miscarriages. I’ve never been pregnant, but can imagine how sad I’d feel if I finally conceived a child, only to lose him or her. Ugh.

    But, I wish you all the best — do let me know if the B12 makes a difference. I hope it will….warm fuzzy baby thoughts going your way!


  30. Your site has been very helpful-I have started taking a liquid form of b12 and was searching to see how it would affect me getting pregnant -I had no idea the 2 could be linked. After 2 serious miscarriages -this b12 could be just what I need. Wish me luck!

  31. You should write an article based on the B12 issue of infertility using your own words – drive more traffic to your blog too. Just a thought. I’m guessing many people struggling to get pregnant don’t know this simple tip.

    Happy holidays.