Maternal Hypothyroidism And Fetal Brain Development

Maternal Hypothyroidism and Fetal Brain Development

Thyroid hormones play a critical role in fetal brain development. The fetus depends entirely on maternal thyroid hormones for the first 12 weeks of pregnancy, until the baby’s thyroid begins to produce thyroid hormones on its own. For the first trimester the baby is completely dependent on the mother for thyroid hormones necessary for brain development. Babies born to mothers with undiagnosed or inadequately treated hypothyroidism are at risk for lower IQ scores and learning disabilities. Despite the mounting evidence, thyroid screening is currently NOT mandatory in pregnancy. It is SHAMEFUL that countries around the world do not set health policies to protect our babies.

Thyroid screening should be MANDATORY for every pregnant woman worldwide.

Thyroid Screening in Pregnancy

In a 1999 study published in The New England Journal of Medicine, researchers recruited women who had tested positive for hypothyroidism during pregnancy as determined by a high TSH level, along with a control group of women with normal TSH levels. Their 7 to 9  year old children at the time of the study underwent 15 tests related to intelligence, attention, language, reading ability, school performance, learning problems, and visual-motor performance. The children were grouped according to whether their mother’s hypothyroidism had been treated during the pregnancy. Researchers discovered:1

“The larger deficits in performance were found among the children of the untreated women; their scores for all 15 tests were worse than those of the control children. Their average full-scale IQ score on the Wechsler Intelligence Scale for Children, third edition, was 7 points lower, and 19 percent of the children of women with hypothyroidism had an IQ score of 85 or lower, compared with 5 percent of the control children.

The current study shows that hypothyroidism in pregnant women can adversely affect their children’s subsequent performance on neuropsychological tests. Decreases in performance can occur even when the the pregnant woman’s hypothyroidism is mild and probably asymptomatic.”

Given the growing body of scientific evidence showing the dangers of maternal hypothyroidism on fetal brain development, why is thyroid screening not mandatory for every pregnant woman worldwide? Why take chances with our babies?

The Endocrine Society

According to the Endocrine Society “Management of Thyroid Dysfunction during Pregnancy and Postpartum” clinical practice guidelines:2

Recommendation #1:

Both maternal and fetal hypothyroidism are known to have serious adverse effects on the fetus. Therefore maternal hypothyroidism should be avoided. Targeted case finding is recommended at the first prenatal visit or at diagnosis of pregnancy.

 Wait…Rewind…Targeted Case Finding For Hypothyroidism?

The Thyroid Federation International estimates there are up to 300 million people worldwide with thyroid dysfunction, majority women, yet over half are unaware of their condition.3 Over 150 million thyroid sufferers remain undiagnosed worldwide. They have no clue and clearly their doctors have no clue. With targeted case finding, many pregnant hypothyroid women will continue to fall though the medical cracks and their babies will be in danger.

American Thyroid Association

According to the Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum:4

Recommendation 72:

There is insufficient evidence to recommend for or against universal TSH screening at the first trimester visit.

The president of the American Thyroid Association, Dr. Kenneth D. Burman, was quoted in The New York Times 2009 article Prenatal Testing of Thyroid Is Debated:

For now, medical societies advise testing only high-risk women.

As a matter of policy, Dr. Kenneth D. Burman, the president of the American Thyroid Association, agrees with that stance for now. Yet like more and more endocrinologists, he offers T.S.H. pregnancy testing in his practice, at Washington Hospital Center in Washington.

“Every patient I see who’s considering getting pregnant or is pregnant gets a thyroid function test,” he said. “And I think that’s the right thing to do.”

The President of the American Thyroid Association stated that he tests every patient considering getting pregnant or is pregnant. WAIT!! What about all the doctors who don’t know this? What about all the doctors in the world who don’t test their pregnant patients? What happens to their babies? The medical societies are playing a very risky game with our babies. I for one will fight like a warrior to ensure a change in health policy to mandate thyroid screening in pregnancy. I won’t rest until this happens.

The Next Global Thought Leader

I am proud to announce that I’ve been named in the top 25 for Season 1 of Change the World: The Search for the Next Global Thought Leader. From here, the 25 quarter-finalists will be reviewed by an esteemed panel of thought leader judges, who will select the Top 10 candidates. These semifinalists will compete in online challenges to see who will be the 2013 Next Global Thought Leader!

The winner of this competition will win massive social media exposure to achieve their mission. The mission of Hypothyroid Mom is clear – mandatory thyroid screening for every pregnant woman worldwide. I will save babies. I know deep inside me that this is what I am destined to do. I’ve known it since that cold winter day in January 2009 when I lay waiting on a medical exam table for my D&C. I lost my unborn baby so unnecessarily to hypothyroidism and I vowed that day I would never let this happen to another baby again.

YouTube Preview Image



  1. Haddow, J.E. et al. Maternal Thyroid Deficiency During Pregnancy And Subsequent Neuropsychological Development Of The Child. The New England Journal of Medicine, 1999 Aug 19; 341(8):549-555
  2. Endocrine Society. Management of Thyroid Dysfunction during Pregnancy and Postpartum: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism, 2007 August; 92(8)(Supplement):S1-S47
  3. Thyroid Federation International. International Thyroid Awareness Week. Retrieved from:
  4. Stagnaro-Green, A. et al. Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum. Thyroid, 2011 October; 21(10): 1081-1125

Take Back Your Thyroid Health! Sign up and never miss a post - it's FREE

About Dana Trentini

Who knew that little butterfly-shaped thyroid gland at the base of my neck could affect my life so completely? I founded Hypothyroid Mom in memory of the unborn baby I lost to hypothyroidism. Winner of two 2014 WEGO Health Activist Awards: Health Activist Hero & Best In Show Twitter. *Hypothyroid Mom includes Affiliate links. Connect with me on Google+


  1. Peter F says:

    I tell every one of my friends at work or in social gatherings who I learn is pregnant or getting pregnant to make sure they get their thyroid tests done and to read your posts. You mission is accomplished with me !!!!

    • Dana Trentini says:

      Peter, Thank you for helping to spread awareness among your friends and family!

      • Peter F says:

        Well I just want to say that you really helped me too. I did all the tests and found that my thyroid is functioning just fine. Just the same – your drive and determination to take control of your health and to question professional advice given to you inspired me. I began treating my doctor just like my accountant and lawyer a professional I am hiring who is accountable to me and whose advice I will listen to and weigh against what other experts are saying. Without first getting approval I sought out the help of other experts who were able to build on the more limited framework that my family doctor was working from. In time my doctor grew to respect that I was actively involving others in my own health plan. He is happy that I am keeping him included and especially happy that I provide him with notes and records I receive from consulting with others. While I don’t have a thyroid problem – following your lead has really empowered me to get to the root of my problem – and I feel I am very very close. While it isn’t 100% solved yet I am in a much better place today because of the effort so far and I feel calm and serene and feel that my children are benefiting from the greater love and attention a patient man can pay to them. I support your effort unconditionally.

        • Dana Trentini says:

          I’m so happy you took charge of your health and started your own research. We all have to be advocates for ourselves. Best wishes to you for good health and thanks for the support for Hypothyroid Mom!

  2. Hi Dana
    Thank you for sharing this information with everyone.
    I was wondering why, i could find no reference on your website at all about hypothyroidism prevention. For example Dr. Richard & Karilee Shames have written two books, including one titled “Thyroid Power”, which warns against fluoridation in water and in products such as tooth paste. Fluoride actually happens to be an extremely toxic substance.
    Did you know that a single tube of bubble-gum flavored Colgate-for-Kids toothpaste contains enough fluoride (143 mg) to kill a child weighing less than 30 kg. (Whitford 1987a)?
    It is a well known fact that kids consume some of the toothpaste they use and a lot of it gets absorbed in the body.
    97% of western Europe has rejected water fluoridation, and i am sure they have a good scientific reason to do so.
    Have you done any research on this matter, and have you changed your fluoride consumption?
    Thank you.

    PS For anyone who is willing to educate themselves on the toxicity of fluoride, check out

  3. It’s not all that easy when you already ARE hypothyroid before becoming pregnant. Luckily for me, my tsh was low enough where it wasn’t a concern by that point, but we have been trying to find the right dose of medication/right medication for 2 years now. It wasn’t just a magical snap of the fingers to get on track.

    • Dana Trentini says:

      Hi Amy, I hear you. It is an uphill battle for many of us Amy. Absolutely. It is very unfortunate the lack of awareness in the medical community about our condition. The first step Amy is to be sure you’ve had full testing. Often times TSH is the only test done. If you haven’t already, be sure to request testing for Free T4, Free T3, Reverse T3, thyroid antibodies (TPO-Ab and TgAb), adrenals, iron testing including ferritin, sex hormones, D3, B12, magnesium, zinc and selenium. You don’t mention which medication you are on. Levothyroxine drugs like Synthroid are the gold standard for treatment. Unfortunately they don’t work for all of us. Take a look at this post with various thyroid medications and factors to discuss with your doctor in case your thyroid medication is the reason you are not optimally treated.

  4. I want to thank you for this article, I have had Hashimotos for over 6 years now and was wrongly prescribed antidepressants among the ‘traditional’ t4 only medication for such a long time. I have only just found a doctor after all those years that will actually test for free T3, RT3 and the other ones you mentioned (which all tests should be standard practice). I have had a miscarriage and am utterly scared of getting pregnant again, it is somewhat because of the fear that I could loose another child but mainly for me its the fear that I could of had a healthy baby if I had just had the random luck of having an informed doctor. I am glad you are fighting for this as it is an issue that needs to be addressed. I am really sorry for your past loss and want you to know you are and will save thousands of babies lives in the future. I thank you from the bottom of my heart.

    • Dana Trentini says:


      Your message brought tears to my eyes. I hope to save babies in my mission to mandate thyroid screening in pregnancy. Thank you. I am sorry for the loss of your baby. There is hope to have healthy babies now that you have the doctor open to doing all the testing. Best wishes to you. Welcome to Hypothyroid Mom!

  5. Jackie R says:

    I am almost 8 weeks pregnant and was just diagnosed today with hypothyroidism with TSH levels of 14.8 and would be considered “low-risk.” My doctor immediately prescribed me synthetic hormone and referred me to endocrinologist. When I started doing research and discovered through this article that many doctors don’t do these types of screenings I was shocked and saddened. Keep up the good work! I am so blessed to have had access to this level of care and all pregnant mamas need to be aware. Thank you so much for spreading the word.

  6. Hi I just wanted to share that I had undiagnosed thyroid cancer while pregnant with my third-it wasn’t until she was about 18 months I was actually diagnosed. Thank God she had no birth defects but sadly she has a lower IQ, she struggles to retain information and is falling further behind.
    I have two questions which you may not be able to help me with but worth a shot!
    1. Is there anything I can do to help my daughter Molly? I have been wondering if add medication may help her concentration and ability to focus better?
    2. She turns 8 next week and is a bit overweight and despite lots of exercise and healthy diet she only seems to be putting more weight on-should I insist on a blood test to get her thyroid levels checked?

    Thanks from Oz

    • I was diagnosed with hypothyroidism almost one year to the day I gave birth to my son. I have a feeling that I was hypo before I became pregnant (my tsh at diagnosis was 64). As if dealing with the effects of the disease wasn’t hard enough, I am terrified of the impact it may have on my son. Did you ever find any help for your daughter? Any help or advice would be most appreciated.

  7. Hai mam
    i am 26 wks pregnant now. My 1st trimester tsh value was4.41. 2nd trimester was 3.05 and now its 3.72. iam on medication from 1st trimester onwards. my usg reports are normal. Is there any worried issues?

    • HI Anu –
      I have similiar thoughts/levels – my TSH at 4weeks was 4.4. – they up’d my levothyroxine dose (thank goodness) but they have yet to test me again – and are refusing because they think 4.4TSH is normal! I am soo upset. Please let me know how you made out. 🙂

  8. christine says:

    i am 8 weeks also and was just told that my TSH was 18, but i had already been well aware of my hypothyroidism. They want me to go see a genetic counselor, as well as to go see maternal-fetal medicine. i’m really concerned about if the baby will be okay or not, and of course all the google sites have me convinced there will be something seriously wrong. Has anything new come of your situation and your TSH?

  9. I only found out about my pregnancy wen I was 12 weeks pregnant, I don’t get my period every month, but I’m on thyroid meds now, I’m worried cos my 1 pregnancy only went on thyroid meds @ 22 weeks, my son is 5 years now, and he doesn’t speak, I’m worried about the bby I’m carring, I’m 20 weeks now. I’m worried cos 4 first 12 weeks I wasn’t on thyroid meds

    • Hi Dana, thank you for the blog.
      Happy I found info on hypothyroidism, especially from mothers.
      I’m on 13wk of my 3rd pregnancy. My blood test at 10wks showed TSH at 16.4. Was referred to a specialist and has been given PTU.
      1st child aged 5, has slight delay in speech and 2nd aged 2, is developing normally.
      There isn’t much on the net about the effects on babies. And all related info is very negative. So is it true that they’ll difinately have some form of disorder??
      I understand my fears are incomparable to your losses. But would like to keep mom’s updated on my case.

  10. Thanks Mrs. Dana Trentini. This article is very helpful for my family and friends. This article has very easy discus about hypothyroidism. I also want to try follow this tips for my first pregnancy. Thanks you for the information.

  11. Hi,
    I have few doubts, if you can help me to clear those doubts it will be of great help.
    I am blessed with a boy baby 20 days back. During new born screening it is found that he is having high TSH level (135). Immediately we were advised to do neuclear medicine scan for the baby and found that there is a thyroid gland and it is not secreting thyroid harmones. Doctor advised to give 37.5mg dose of tablets to the baby every day. we started giving this tablet from 16th day from the birth of the baby. My wife’s thyroid level was normal during 7th month’s test(report showed 3.5). she didnt take any tablet for thyroid during pregenency.
    My Doubts:
    1. Does the brain development of my baby affected during pregenency?
    2. Medicine started at 16th day.. Is this right? or during first 15 days does my baby’s develpemt got affected?
    2. Do you have any suggession?

  12. Jennifer Ore says:

    Hello! I just wanted to share my experience with low thyroid and pregnancy. I have a 20 year old son who has low IQ and cerebral palsy. He also has epilepsy. When I was 18 years old I was diagnosed with thyroid cancer. I had all of my thyroid removed and was placed in synthroid. At the age of 24 I became pregnant with my third child, my son. We knew right away that things were different with him. We sought a diagnosis for May years to no avail. Finally about 10 years ago I began to question whether or not my thyroid condition could have played a part. After much research and carrying responses, I am 99.9 % certain that his disabilities are related to maternal hypothyroidism. I STRONGLY agree with early thyroid screening during pregnancy! Thank you for the work you have put into this!

  13. i have TSH level of 9.5 in my blood report and my gp did not see it until i go to the maternity doctor and was not treated
    i am in 13th week now ans starting treatment
    I am worried now thinking it might have harm my baby
    please advise would starting treatment from 13th week help my baby

  14. I think women should be tested before they get pregnant if this is the case. I didn’t find out that my thyroid was deficient until I went to see my naturopath with my bloodwork results. By then my son was already 8 years old & had already been diagnosed with severe ADHD and severe ODD. Since then, they’ve added Anxiety with Dysphoria & Tourette’s. She put me on a microdose of Liothyronine XR (which has to be compounded), a bio-identical form of T3 hormone.

  15. and let’s not forget the effects of potassium bromide used on berries as a pesticide. the bromine competes with iodine and can create problems of iodine uptake. and where is the discussion about GMO; genetically modified organisms on the thyroid gland? the FDA just unleashes this stuff on the public and we, as the public , which pay THEIR salary have to be the watchdogs and cleanup crew. this is despicable. I would encouraged everyone to watch the movie “Bought”

  16. I was diagnosed with hypothyroidism at 12 weeks pregnant. So annoyed as I had the bloods taken weeks earlier but no one bothered look over them until my visit. I then was put on thyroxin 100mg which was later increased to 150mg. My question is because I wasn’t treated until into the second trimester, is my baby (now 9mths old) likely to have been affected? He is behind in his motor and speech development so I wonder if it’s a result of thyroid or if he’s just a slow starter.


  1. […] Newborn with deficits in intellectual development […]

  2. […] they give birth to children with conditions including autism, intellectual deficits, and ADD/ADHD, and doctors miss the […]

Speak Your Mind