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  • Pregnancy and Thyroid Imbalance Part 2: Miscarriage, Pregnancy and Thyroid Imbalance

    Miscarriage and Thyroid Imbalance

    Miscarriage is a traumatic, and for many, a devastating time in one’s life and even more so if repeated.

    A high rate of recurrent miscarriages has been demonstrated among women with thyroid imbalances 1, 2, 3, 4. Even minimal thyroid imbalance can cause recurrent miscarriages and inability to carry a normal pregnancy. A study in 2011 found that the presence of thyroid antibodies increased the risk of miscarriage by 290% 3.

    “A woman with untreated hypothyroidism is at the greatest risk for a miscarriage during her first trimester. Unless the case is mild, women with untreated hyperthyroidism are also at risk for miscarriage” 5.

    There is a lack of awareness even among many doctors of the dangers of thyroid imbalance in pregnancy. Be the advocate for yourself and your baby - insist on thyroid testing if you have any thyroid symptoms. You will find a list of symptoms on several websites 6, 7, 8, 9.

    There is so much suffering, guilt, and depression exacerbated by hypothyroidism. Ask your doctor for thyroid testing and ensure any thyroid imbalance is corrected before becoming pregnant to avoid further issues with pregnancy and your baby. If you have thyroid antibodies, you have an autoimmune disorder and research shows that if you have one, you are likely to have others.

    During pregnancy ensure your thyroid levels are monitored frequently. Find a doctor who listens to you and who will support you throughout your pregnancy and following the birth of your baby. Whenever you feel something is not right do not delay, talk to your doctor and ensure you have the tests you need whether you are on thyroid treatment or not.

    The Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease during Pregnancy and Postpartum 4, recommend that women with Hashimoto’s, should have their TSH “evaluated every 4 weeks during the first half of pregnancy and at least once between 26 and 32 weeks gestation. TSH levels above the trimester-specific pregnancy reference range should be treated 9. Dana Trentini, on her website HyopthyroidMom includes the ideal TSH levels for each trimester namely, first trimester, 0.1-2.5 mIU/L; second trimester, 0.2-3.0 mIU/L; third trimester, 0.3-3.0 mIU/L” 3. Those on thyroid treatment will need monitoring more frequently.

    Pregnancy, Birth and Thyroid Imbalance

    An overwhelming number of hormonal changes during pregnancy and postpartum can trigger an adverse thyroid reaction. Also undiagnosed or improperly managed thyroid problems can lead to complications with pregnancy and birth and can increases the chances of pre-eclampsia, miscarriage, premature birth, low birth weight, anaemia and stillbirth 5, 10, 11

    Graves Disease is the most common form of hyperthyroidism (overactive) in pregnancy and 1 in 1500 women will be affected.

    The more common thyroid imbalance, hypothyroidism (underactive), is an autoimmune disease, Hashimoto’s Thyroiditis.

    “According to the American Thyroid Association, 10% to 20% of all pregnant women in the first trimester of pregnancy are positive for Hashimoto’s antibodies” but are told they are euthyroid. Based on their TSH level (Thyroid Stimulating Hormone) they have normal thyroid functioning 3. Although they appear and may feel normal, they have subclinical Hashimoto’s Thyroiditis, where their body is silently responding to and destroying their own thyroid gland. “A significant percentage of these women will develop a TSH above the trimester-specific pregnancy reference range by the third trimester, endangering the life of their fetus" 3.

    Both hyper and hypothyroidism can have adverse impacts on mum and baby, so it is essential to take ownership of your health during pregnancy 11.

    In Part 3 we will explore Thyroid Imbalance Postpartum


    1.  Arem, R. (2007). The Thyroid Solution. Ballantine Books: New York.

    2.  Stagnaro-Green, A. (2011). Thyroid Antibodies and Miscarriage: Where Are We at a Generation Later?

    3.  Trentini, D. (2012). Hashimoto’s Disease: The Danger of Thyroid Antibodies and Pregnancy

    4.  Stagnaro-Green, A., Abalovich, M., Alexander, E., Azizi, F., Mestman, J., Negro, R., Nixon, A., Pearce, E.N., Soldin, O.P., Sullivan, S., and Wiersinga, W. (2011). Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum.

    5. Thyroid Awareness. (2016). The Thyroid and Pregnancy.

    6.  Hashimoto’s Awareness. Checklist of Hashimoto’s Symptoms.

    7.  Roman. A. Hyperthyroidism During Pregnancy.

    8.  Hansen, G. M. (2016). Hashimoto's Thyroiditis - A New Path of Learning and Discovery (Parts 1 - 4).

    9.  Trentini, D. (2012). Your Postpartum Fatigue Could Be A Sign Of Thyroid Problems.

    10. NIH. (2012). Pregnancy & Thyroid Disease.

    11. Katie - Wellness Mama. (2017). How Thyroid Disease Affects Pregnancy and Fertility.