Vit B12 deficiency and pregnancy

My daughter is 25 and is 18 weeks pregnant. She has had symptoms of Vitamin B12 deficiency for some time and we finally got the GP to agree to check her levels last week (only because I went with her and pleaded her case). Her serum level was 140. I know it can be artificially low with pregnancy but can anyone advise as to how much the level is affected by pregnancy, and what should happen now? The GP has given her 1 hydroxocobalamin injection and is seeking advice as to whether she should get the full loading doses and ongoing injections or not. I feel she should be fully treated as her symptoms are identical to mine were prior to my diagnosis and I worry hugely that not treating will affect the pregnancy. Thanks

11 Replies

  • B12 can get lower in pregnancy, but that's mostly in the third trimester. She very likely has a defieciency and should be given treatment. She should get the full loading dose! It's double important now of course. I assume she was taking folate already, maybe even a pregnancy-multivitamin? Continue with those as well. But treatment in pregnancy is no different than normal, same applies. Actually most women find that they need more injections in pregnancy to feel well.

  • Brilliant - thanks for that. You've confirmed what I thought. Let's hope the GP agrees! I have to battle to get treated properly for my deficiency. Yes, she is taking folate and multivitamin.

  • It might help to have identified the symptoms that she had and when they started - and hopefully that will make it very clear that it isn't related to the pregnancy if the symptoms started before.

  • Hi - she's had her symptoms for probably a year now although some have got increasingly worse. She is constantly tired - falls asleep all the time; brain fogging; terrible memory; abdominal problems; difficulty concentrating. She asked to get her B12 done before she was pregnant and was then told it was fine. It had never been done! We found that out last week. I feel angry - I really hope this delay has not led to her baby suffering any problems. Thanks

  • She should have the loading daughter was discovered, finally, deficient during her last pregnancy and received only one injection; it was then three monthly. She had been symptomatic for a couple of years without being diagnosed until this point; but because they did not give loading doses it took a very long time for her levels to rise and her to become somewhat better. She has permanent damage to the nerves in her fingers with some loss of feeling. She definitely says that it took so long because of not receiving enough to start with. My other daughter received injections very soon after we noticed symptoms, (due in part to her sister's experience) and she received correct treatment and picked up much more quickly.

    My other daughter has just been through pregnancy and had monthly injections and 5mg folic acid throughout, with no adverse effects - in fact quite the opposite; she has felt better during pregnancy than the couple of years previously.

  • Thanks for this. I am going back to the GP with her later today and I will plead her case to be given the full loading dose. She too has been symptomatic for some time.


    Pregnancy creates high demands on B12 as well as other vitamins and is involved in building DNA, so it's vital that your daughter is treated adequately.

    The excellent book, "Could it be B12? An Epidemic of Misdiagnoses", by Sally Pachlok, has extensive information on B12 in pregnancy:

    "B12 is critical before conception, during pregnancy and during breast feeding. A Serum B12 falling in the 'grey zone' is not adequate for prenatal or postnatal care. Moreover, prenatal vitamins do not contain enough B12 to correct a deficiency or beginning deficiency, and a growing foetus in the womb needs plentiful amounts of B12, which pregnancy can deplete (see chapter 12)".

  • Thank you for replying. Good news - the GP agreed tonight to give her 6 loading doses and then 2 monthly injections for the foreseeable future. One happy mum!

  • That's great snowflake16.

    I notice though that you say your daughter has symptoms similar to yours, which included peripheral neuropathy and memory loss.

    According to the BNF guidelines these neurological symptoms should be treated every other day until no further improvement - especially important for daughter's B12 levels in pregnancy!

    It is also important to find out why she is so deficient ?

    I hope ll goes well for you both.

  • Thanks Polaris. I appreciate you replying. She doesn't have any neuropathy but did have the brain fogging and bad memory loss. The GP wouldn't give me any more loading doses either and will only give me 3 monthly injections - I therefore supplement myself. I think I was so happy he at least agreed to give her loading doses (he was sure it was all due to her being depressed - which she isn't) I stopped pushing. I will suggest to her to ask the Practice Nurse to persuade the GP to reconsider further loading doses. I also asked the GP if he would test her for antibodies - which he agreed to. It's just never straight forward is it??

  • No, I agree snowflake - never straight forward and everyone has to tippytoe in case of upsetting the surgery ! So you're doing really well to get injections at all as well as further testing.

    My daughter had fertility problems and eventually a healthy baby but then post natal depression - I wish I'd known about the B12 effects back then. Very best wishes to you both.

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