Pregnancy Loss Causes and Risk Factors Can Hypothyroidism Cause Miscarriage? By Krissi Danielsson Krissi Danielsson, MD is a doctor of family medicine and an advocate for those who have experienced miscarriage. Learn about our editorial process Krissi Danielsson Reviewed by Reviewed by Rachel Gurevich, RN on June 03, 2019 facebook twitter linkedin Rachel Gurevich, RN, is a registered nurse, fertility advocate, author, and recipient of The Hope Award for Achievement, from Resolve: The National Infertility Association. Learn about our Review Board Rachel Gurevich, RN Updated on February 28, 2020 Print Getty Images/vgajic Table of Contents View All Thyroid's Role What Is Hypothyroidism Underactive Thyroid/Pregnancy Hypothyroidism and Miscarriage Symptoms of Hypothyroidism Thyroid Hormone/Pregnancy If you've been diagnosed with hypothyroidism — or an underactive thyroid — you may be wondering if it may cause problems during pregnancy or even a miscarriage. In fact, hypothyroidism is linked to miscarriages so it's important to be able to recognize the signs of this condition. Understanding the Thyroid's Role The thyroid is a gland in your neck (above your collarbone) that produces hormones involved with many of your body's activities. It plays an important role in your body's metabolic and hormone balance. When something's off with your thyroid, there's a good chance the rest of your body and its processes — including pregnancy — will be affected. What Is Hypothyroidism? Thyroid hormone controls your body's metabolic processes. When you have hypothyroidism, the thyroid does not produce enough thyroid hormone to keep these processes going at their normal rate, and they start slowing down. This can affect many aspects of your health, including whether you have a healthy pregnancy. An Underactive Thyroid During Pregnancy It's important that your thyroid is functioning normally during your pregnancy, both for your health and your developing baby's health. There are several complications that can occur in pregnant women with hypothyroidism: PreeclampsiaAnemiaLow birth weightStillbirthRarely, congestive heart failure can occurMiscarriage Hypothyroidism and Miscarriage Risk — What the Research Shows Research suggests that having an underactive thyroid may be linked with some types of pregnancy loss. Studies have found that subclinical hypothyroidism (SCH) could mean an increased risk of placental abruption and preterm delivery, both of which can result in later pregnancy loss. The evidence is less clear about a link between hypothyroidism and first-trimester miscarriage. Some studies suggest that thyroid autoimmunity (TAI) may be linked to first-trimester miscarriage, but other studies contradict the link and the matter is still up for debate. A Chinese study published in 2014 found that women with both subclinical hypothyroidism and thyroid autoimmunity have a greater risk of miscarriage between weeks 4 and 8 of their pregnancies. Recognizing the Symptoms of Hypothyroidism According to the U.S. National Library of Medicine, symptoms of hypothyroidism include: FatigueWeight gainA puffy faceCold intoleranceJoint and muscle painConstipationDry skinDry, thinning hairDecreased sweatingHeavy or irregular menstrual periods and fertility problemsDepressionSlowed heart rate If you are concerned that you may have hypothyroidism, ask your doctor about screening. He or she can make a diagnosis based on your symptoms and a simple blood test. Thyroid Hormone During Pregnancy If you do have an underactive thyroid, you will be treated with a synthetic thyroid hormone called levothyroxine. Synthetic levothyroxine is identical to your natural thyroid hormone and is safe for your developing baby. If you were already on levothyroxine before you got pregnant, your doctor will probably increase your dose during your pregnancy to maintain your normal thyroid function. It's best to talk to your doctor about your dose before you become pregnant. During your pregnancy, your thyroid function should be checked every 4 weeks until mid pregnancy and then at least once close to 30 weeks. Was this page helpful? Thanks for your feedback! Get diet and wellness tips delivered to your inbox. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. US National Library of Medicine. Thyroid diseases. Updated February 2020. Endocrine Society. Hypothyroidism and pregnancy. Updated July 2018. Maraka S, Ospina NM, O'keeffe DT, et al. Subclinical Hypothyroidism in Pregnancy: A Systematic Review and Meta-Analysis. Thyroid. 2016;26(4):580-90. doi:10.1089/thy.2015.0418 Lazzarin N, Moretti C, De felice G, Vaquero E, Manfellotto D. Further evidence on the role of thyroid autoimmunity in women with recurrent miscarriage. Int J Endocrinol. 2012;2012:717185. doi:10.1155/2012/717185 Liu H, Shan Z, Li C, et al. Maternal subclinical hypothyroidism, thyroid autoimmunity, and the risk of miscarriage: a prospective cohort study. Thyroid. 2014;24(11):1642-9. doi:10.1089/thy.2014.0029 US National Library of Medicine. Hypothyroidism. Updated February 2020. Alexander EK, Pearce EN, et al., 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease during Pregnancy and the Postpartum. Thyroid. 2017;(10)5:3-7. doi:10.1089/thy.2016.0457 Additional Reading Allan, W.C., J.E. Haddow, G.E. Palomaki, J.R. Williams, M.L. Mitchell, R.J. Hermos, J.D. Faix, R.Z. Klein, "Maternal thyroid deficiency and pregnancy complications: implications for population screening." J Med Screen 2000. Accessed 8 May 2008. Casey, Brian M., Jodi S. Dashe, C. Edward Wells, Donald D. McIntire, William Byrd, Kenneth J. Leveno, and F. Gary Cunningham, "Subclinical Hypothyroidism and Pregnancy Outcomes." Obstetrics & Gynecology 2005. Accessed 8 May 2008. Hypothyroidism. MedlinePlus. U.S. National Library of Medicine. January 15, 2016. Pregnancy and Thyroid Disease. National Institute of Diabetes and Digestive and Kidney Diseases. April 2012. Sieiro, Netto L., C. Medina Coeli, E. Micmacher, S. Mamede Da Costa, L. Nazar, D. Galvao, A. Buescu, and M. Vaisman, "Influence of thyroid autoimmunity and maternal age on the risk of miscarriage." Am J Reprod Immunol Nov 2004. Accessed 8 May 2008. Subclinical Hypothyroidism Increases Early Miscarriage Risk. Medscape. November 25, 2014. Thyroid Disease and Pregnancy. American Thyroid Association.