Should all women be screened for thyroid dysfunction in pregnancy?

Does anyone here disagree with universal screening for thyroid disorder in pregnancy?

I really have only two problems:

How do you treat those who are found to have minor thyroid disturbances?

The screening should include pre-conception screening, at least to the point of making it readily available and publicising it. If nothing else, it might help to identify the changes that have occurred later, in pregnancy.

Womens Health (Lond Engl). 2015 Jun;11(3):295-307.

Should all women be screened for thyroid dysfunction in pregnancy?

Taylor PN1, Okosieme OE1, Premawardhana L1, Lazarus JH1.

Author information

• 1Thyroid Research Group, Institute of Molecular & Experimental Medicine, Cardiff University School of Medicine, Cardiff, UK.


The subject of universal thyroid screening in pregnancy generates impassioned debate. Thyroid dysfunction is common, has significant adverse implications for fetal and maternal well-being, is readily detectable and can be effectively and inexpensively treated. Furthermore, the currently recommended case-finding strategy does not identify a substantially proportion of women with thyroid dysfunction thus favoring universal screening. On the other hand subclinical thyroid dysfunction forms the bulk of gestational thyroid disorders and the paucity of high-level evidence to support correction of these asymptomatic biochemical abnormalities weighs against universal screening. This review critically appraises the literature, examines the pros and cons of universal thyroid screening in pregnancy, highlighting the now strong case for implementing universal screening and explores strategies for its implementation.


child neurodevelopment; hyperthyroidism; hypothyroidism; isolated hypothyroxinemia; levothyroxine; pregnancy; screening; subclinical hypothyroidism

PMID: 26102469 [PubMed - as supplied by publisher]

21 Replies

  • Helvella, I'm certainly in favour of universal testing as soon as pregnancy is confirmed and if a woman has difficulty conceiving she should be tested then too.

    Minor thyroid disturbances should be treated to 'correct' levels rather than risk developmental problems in the foetus.

  • I fully agree with you 100percent.

  • Personally I think from experience in our family that thyroid screening should be done routinely in pregnancy. Shortly after my wife's second pregnancy, Hashimoto's thyroiditis became obvious and ultimately destroyed her thyroid. The problem is twofold: a) the act of pregnancy itself and b) the fact that it is caused by the genetic melding of two individuals; mum and dad. If that causes genetic clashes, then adverse results can occur. I think that the evidence shows that this happens far more than people think. Usually the problem sorts itself out with time postpartum but too often it doesn't. Note: pregnancy is a traumatic time for a woman - her thyroid balance is severely altered by the demands of the growing foetus, and the strain for some can be too much and irreversible.

  • They should also be tested after the baby is born - as low thyroid can be implicated in PNB - Post Natal Blues !

  • Fact: hypothyroidism while pregnant is not good for the fetus.

    Problem: If a high TSH is revealed while pregnant, a doctor will prescribe levothyroxine to bring the TSH down. This does not, however, mean that thyroid levels (T4 and/or T3) really increased to optimal levels. And if there are iron, cortisol, or other issues, the T4 may not be tolerated.

    In a healthy woman, I believe other hormones besides TSH lead to increased T4 production. So even though a woman could be somewhat hypo, she MAY produce more on her own than if given levo and dosed by TSH.

    The pros and cons leave me undecided.

  • I have read that when thyroid hormones are low in the Mother - that the foetus will produce its own growth hormone to compensate and result in bigger babies. Any baby over 8.5 lbs may indicate a Hypo Mum - this was mentioned in Dr Peatfield's book.

  • Big babies are associated with hypothyroidism - but I had not seen that mechanism suggested.

    It does make you wonder about the story linked below. Which does NOT mention thyroid. Perhaps it should have?

    [I][B]Rise of the sumo baby [/B]

    The number of large babies weighing 10lb or more at birth has jumped by a fifth. What is behind this boom in hefty newborns? And how has it changed pregnancy and labour? Viv Groskop talks to mothers, doctors and midwives [/I]

  • Amazing that thyroid was not mentioned. There was/is some research going on about giving metformin to pregnant Mums who are overweight to prevent diabetes later in life in their children. It was an article in the Sunday Times - as I remember. I wrote to the people running the research and mentioned thyroid testing should be more thorough first before giving metformin. As we know the aforementioned causes B12 deficiency - so yet more problems.... The reply was long and patronising and did not address my question - why not test the Mums thoroughly for thyroid.... ? What a scandal....

    PS My daughters were just under 9lbs and 9.7 - so was obviously Hypo almost 50 years ago !

  • Good thinking Marz. Have just had to query Doctors lowering of my son's Levo this morning and let him know that Metformin can lower TSH. What have the medical profession got against any Thyroid problem?

  • Didn't know it could affect TSH - I know it can stifle B12 - but am not sure of the mechanism....

    Oh dear sorry to read about your son....hope you were able to keep the status quo....

  • I agree that it should be tested after the baby is born.

    I was diagnosed with PND and given AD's after my daughter was born.

    I put three stone on whilst pregnant and lost only a stone after having my daughter.

    Then as the months went on I put more weight on, my hair was falling out and suffered extreme fatigue and of course the depression and shocking PMT. I also got the most terrible thoughts and anxiety.

    Not once did my G.P. mention thyroid or tested it.

    Now this could have been PND but now I am hypo. and know the symptoms it does make me wonder I was suffering from it then.

  • Testing before may well produce a baseline that would indicate if results are not normal afterwards too .... Sorry to read you were possibly mis-diagnosed - we read it so often don't we ?.....

  • When I had my babies, doctors didn't 'believe' in post natal depression. I was told to snap out of it and go for a walk! Not surprising I no-longer 'believe' in doctors, is it!

  • Oh no that's awful, but then again I have heard of this before when women were suffering from depression and anxiety they were told "oh it's just your nerves, snap out of it"

    If it was only that simple.

  • If only!

  • So definitely offer testing to women who show signs of post natal depression. Make women aware of the possibility of thyroid disturbance after birth. Those are clear.

    Offer testing before pregnancy to those with a family history of thyroid dysfunction?

    I'd like to see women encouraged to have a screening before getting pregnant for iron, D, B12 and folate.

  • Let us do it properly and add iodine to pre-pregnancy testing.

  • I passionately agree, and further - pregnancy and breast feeding makes huge demands on vitamin B12 and, with more mothers becoming vegetarians, deficiency adversely affects their babies' development, their own health, and possibly thyroid too as these links show:

  • I'm in favour of universal screening for thyroid issues in pregnancy. Also for women who are having difficulties with fertility, ie conception and multiple miscarriages. subtle issues with the thyroid can have massive impacts on women who are trying to conceive or are pregnant. It will certainly be cheaper in the long term to screen for bloods.

  • We have seen a number of members posting that they have got as far as IVF without adequate thyroid testing.

    Of course it is less costly to do the screening properly than to half-heartedly, and long-term, deal with the consequences.

  • I really think girls should be tested from the onset of puberty and maybe once every five years after that so that a baseline is achieved before any pregnancy takes place.

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