Table of ContentsView AllTable of ContentsPotential ChallengesScreening in PregnancyThyroid Hormone ChangesIssues During PregnancyThe Need for IodineFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Potential Challenges
Screening in Pregnancy
Thyroid Hormone Changes
Issues During Pregnancy
The Need for Iodine
Frequently Asked Questions
Verywell / Emily Roberts
Potential Fertility Challenges
Here are some common challenges you can run into when your thyroid disease is undiagnosed, untreated, or insufficiently treated.
Fertility ChallengeYour risk of having what’s known as an “anovulatory cycle,” a menstrual cycle in which your body doesn’t release an egg, is higher.What HappensThough you can still have menstrual periods during anovulatory cycles, you can’t get pregnant since there’s no egg released to be fertilized.
Fertility ChallengeYour risk of having what’s known as an “anovulatory cycle,” a menstrual cycle in which your body doesn’t release an egg, is higher.
Your risk of having what’s known as an “anovulatory cycle,” a menstrual cycle in which your body doesn’t release an egg, is higher.
What HappensThough you can still have menstrual periods during anovulatory cycles, you can’t get pregnant since there’s no egg released to be fertilized.
Though you can still have menstrual periods during anovulatory cycles, you can’t get pregnant since there’s no egg released to be fertilized.
One way to identify anovulatory cycles is through an ovulation predictor kit, which measures a surge of the particular hormones that occurs around ovulation. You may also use a manual or electronicfertility monitoring method, including temperature charting, to identify signs that can indicate ovulation.
Thankfully, proper diagnosis and treatment of your thyroid condition can reduce your risk of anovulatory cycles.Keep in mind that if you’re still having anovulatory cycles once your thyroid function is stable, there are other potential causes that you should explore with a healthcare provider like breastfeeding,perimenopausal changes, adrenal dysfunction, anorexia, ovarian issues, andpolycystic ovary syndrome (PCOS), among others.
Fertility ChallengeYou’re at greater risk of having defects in the luteal phase of your menstrual cycle.What HappensIf your luteal phase is too short, a fertilized egg ends up getting expelled with menstrual blood before it has time to implant.
Fertility ChallengeYou’re at greater risk of having defects in the luteal phase of your menstrual cycle.
You’re at greater risk of having defects in the luteal phase of your menstrual cycle.
What HappensIf your luteal phase is too short, a fertilized egg ends up getting expelled with menstrual blood before it has time to implant.
If your luteal phase is too short, a fertilized egg ends up getting expelled with menstrual blood before it has time to implant.
Pointing to luteal phase defects as the cause of infertility and miscarriage is somewhat controversial since diagnosing them is difficult. Because of this, sufficient evidence hasn’t been found to definitively say that luteal phase defects cause fertility issues, though the research thus far shows that it’s highly likely that they play a role.
Fertility ChallengeYou have a higher risk of hyperprolactinemia—elevated levels of prolactin, the hormone responsible for promoting milk production.What HappensHyperprolactinemia can have a number of effects on your fertility, including irregular ovulation and anovulatory cycles.
Fertility ChallengeYou have a higher risk of hyperprolactinemia—elevated levels of prolactin, the hormone responsible for promoting milk production.
You have a higher risk of hyperprolactinemia—elevated levels of prolactin, the hormone responsible for promoting milk production.
What HappensHyperprolactinemia can have a number of effects on your fertility, including irregular ovulation and anovulatory cycles.
Hyperprolactinemia can have a number of effects on your fertility, including irregular ovulation and anovulatory cycles.
Your hypothalamus producesthyrotropin-releasing hormone(TRH), which in turn triggers your pituitary gland to produce TSH, stimulating your thyroid gland to produce more thyroid hormone. When your thyroid isn’t functioning properly, high levels of TRH may be produced, which can then cause your pituitary gland to also release moreprolactin.
In breastfeeding or chestfeeding individuals, the higher levels of prolactin generated to stimulate milk production often also help prevent pregnancy, illustrating why fertility issues can occur when your prolactin levels are too high and you’re trying to get pregnant.
Understanding Hyperprolactinemia
Charting your menstrual cycleand fertility signs, along with getting a blood test measuring your prolactin level, can help a healthcare provider diagnose hyperprolactinemia. If proper thyroid diagnosis and treatment doesn’t resolve the prolactin issue, several medications like bromocriptine or cabergoline may be prescribed, which can help lower your prolactin levels and restore your cycles and ovulation to normal.
Fertility ChallengeThyroid disease can lead to an earlier onset of perimenopause and menopause.What HappensMenopause may occur before you’re 40 or in your early 40s, shortening your childbearing years and causing reduced fertility at a younger age.
Fertility ChallengeThyroid disease can lead to an earlier onset of perimenopause and menopause.
Thyroid disease can lead to an earlier onset of perimenopause and menopause.
What HappensMenopause may occur before you’re 40 or in your early 40s, shortening your childbearing years and causing reduced fertility at a younger age.
Menopause may occur before you’re 40 or in your early 40s, shortening your childbearing years and causing reduced fertility at a younger age.
Perimenopause, the timeframe prior to menopause when your hormonal levels decline, can last as long as 10 years. And in the United States, the average age of menopause, when you stop having your menstrual period altogether, is 51 years.That means when you have thyroid disease, it’s plausible that you can start having symptoms when you’re around 30.
Take Charge of Your CareDon’t assume that a fertility expert will be on top of your thyroid issues. Surprisingly, some fertility clinics and their healthcare providers don’t pay much attention to thyroid testing or the management of thyroid disease during preconception, assisted reproduction (ART), or early pregnancy. Choose a provider who is thyroid-savvy and develop a plan to ensure that your thyroid disease doesn’t interfere with a healthy pregnancy.
Take Charge of Your Care
Don’t assume that a fertility expert will be on top of your thyroid issues. Surprisingly, some fertility clinics and their healthcare providers don’t pay much attention to thyroid testing or the management of thyroid disease during preconception, assisted reproduction (ART), or early pregnancy. Choose a provider who is thyroid-savvy and develop a plan to ensure that your thyroid disease doesn’t interfere with a healthy pregnancy.
Infertility and Thyroid Disease
In general, universal thyroid screening during pregnancy isn’t considered justifiable, according to the ATA’s guidelines. However, the ATA does recommend that those who are pregnant have their TSH level checked when they have any of the following risk factors:
Obesity, defined as abody mass index (BMI)of over 40, is a common risk factor.
BMI is a dated, flawed measure. It does not take into account factors such asbody composition, ethnicity, sex, race, and age. Even though it is a biased measure, BMI is still widely used in the medical community because it’s an inexpensive and quick way to analyze a person’s potential health status and outcomes.
An Overview of Goiters
Because normal thyroid function is different during pregnancy, your TSH levels will likely change as you progress from the first to third trimester, which a healthcare provider monitors with blood tests. Chief among them is theTSH test, which measures the level of thyroid stimulating hormone in your blood.
Ideally, thyroid disease should be diagnosed and properly treated prior to conception. And if you’re being treated for hypothyroidism and planning to conceive, before you get pregnant, you and a healthcare provider should have a plan to confirm your pregnancy as early as possible and to increase your dosage of thyroid hormone replacement as soon as your pregnancy is confirmed.
Different types of thyroid conditions have different issues when it comes to managing them in pregnancy.
Hypothyroidism
When your thyroid can’t keep up during pregnancy, your TSH level will go up in underactive thryoid conditions, indicating a hypothyroid (underactive) state. If it’s left untreated or insufficiently treated, your hypothyroidism can cause miscarriage, stillbirth, preterm labor, and developmental and motor problems in your child. The ATA recommendation is that, before you get pregnant, a healthcare provider should adjust your dosage of thyroid hormone replacement medication so that your TSH is below 2.5 mIU/L to lower your risk of elevated TSH in the first trimester.
According to the ATA guidelines, thyroid hormone replacement increases should start at home as soon as you think you’re pregnant (ask your healthcare provider for instructions on this) and continue through to around weeks 16 to 20, after which your thyroid hormone levels will typically plateau until delivery.
Hashimoto’s Disease
Hashimoto’s disease, also known as Hashimoto’s thyroiditis, is an autoimmune disease that attacks and gradually destroys your thyroid.Hypothyroidismis a common outcome of Hashimoto’s, so if you’re hypothyroid, you’ll need the same treatment plan mentioned above.
That said, additional attention should be made to keeping your TSH level under 2.5 mlU/L, especially if you havethyroid antibodies, which are often present in Hashimoto’s disease. The higher your TSH level is,the more your risk of miscarriage increases. When you also have thyroid antibodies, research published in 2014 shows that the risk of miscarriage increases even more significantly if your TSH level gets above 2.5 mIU/L.
How Hashimoto’s Disease Is Treated
Hyperthyroidism
If you have lower-than-normal TSH levels while you’re pregnant, this shows that your thyroid is overactive, so a healthcare provider should test you to determine the cause of yourhyperthyroidism. It could be a temporary case that’s associated with hyperemesis gravidarum (a condition of pregnancy that causes severe morning sickness), Graves' disease (an autoimmune thyroid disorder that’s the most common cause of hyperthyroidism), or a thyroid nodule.
How Hyperthyroidism Is Diagnosed
If you’ve been vomiting, have no prior history of thyroid disease, your hyperthyroid symptoms are generally mild, and there’s no evidence of swelling in your thyroid or the bulging eyes that can accompany Graves' disease, a healthcare provider will probably chalk your hyperthyroidism up to temporary gestational hyperthyroidism. A blood test to check for elevated levels of the pregnancy hormone human chorionic gonadotropin (hCG) may also confirm this diagnosis since extremely high hCG levels are often found with hyperemesis gravidarum and can cause temporary hyperthyroidism.
In cases that aren’t as clear-cut, your total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3) and/orTSH receptor antibody(TRAb) levels may be checked, depending on what your practitioner is looking for. These blood tests can usually narrow down the cause of your hyperthyroidism so that a healthcare provider can treat it appropriately.
The Importance of TreatmentYou should begin treatment right away when you’re pregnant and you become hyperthyroid due to Graves’ disease or thyroid nodules. Leaving hyperthyroidism untreated can result in high blood pressure,thyroid storm, congestive heart failure, miscarriage, premature birth, low birth weight, or even stillbirth. For pregnant and non-pregnant people, treatment typically begins with taking antithyroid medications.
The Importance of Treatment
You should begin treatment right away when you’re pregnant and you become hyperthyroid due to Graves’ disease or thyroid nodules. Leaving hyperthyroidism untreated can result in high blood pressure,thyroid storm, congestive heart failure, miscarriage, premature birth, low birth weight, or even stillbirth. For pregnant and non-pregnant people, treatment typically begins with taking antithyroid medications.
How Hyperthyroidism Is Treated
If you’re currently on MMI, a healthcare provider will likely switch you to PTU. It’s unclear which one is better after 16 weeks, so your practitioner will likely make a judgment call if you still need antithyroid medication at this point.
Thyroidectomy: Everything You Need to Know
Graves' Disease
The ATA recommends testing TRAb levels in pregnant individuals in these scenarios:
If you give birth as someone with Graves’ disease, your newborn should be evaluated for neonatal/congenital hyperthyroidism and hypothyroidism, which has serious implications for newborns. In fact, the ATA recommends that all newborns be screened for thyroid dysfunction two to five days after birth.
Congenital Hypothyroidism in Infants
Thyroid Nodules
Thankfully, the vast majority of thyroid nodules aren’t cancerous. The ATA advises pregnant individuals with thyroid nodules to have their TSH level measured and to get an ultrasound to determine the features of the nodule and monitor any growth.
If you have a family history of medullary thyroid carcinoma ormultiple endocrine neoplasia (MEN) 2, a healthcare provider may also look at your calcitonin level, though the jury is still out as far as how helpful this measurement really is.
Thyroid Cancer
When cancerous thyroid nodules are discovered during the first or second trimester—particularly if related to papillary thyroid cancer, the most common type—your practitioner will want to monitor the cancer closely using ultrasound to see how and if it grows. If there’s a fair amount of growth before your 24th to 26th weeks of pregnancy, you may need to have surgery to remove it.
In the case of anaplastic or medullary thyroid cancer, the ATA recommends that immediate surgery is seriously considered.
With any type of thyroid cancer, your practitioner will put you on thyroid hormone replacement medication, if you’re not already taking it, and monitor you closely to keep your TSH within the same goal range as before you were pregnant.
Pregnant individuals should get around 250 mcg of iodine every day. While the majority of people with the capacity to become pregnant in the United States are not iodine deficient, this is also the group that’s the most likely to have a mild to moderate iodine deficiency.
Since it’s difficult to pinpoint who might be at risk of iodine deficiency, the ATA, Endocrine Society, Teratology Society, and American Academy of Pediatrics all recommend that pregnant individuals take 150 mcg potassium iodide supplements daily.Ideally, this should start three months before conception and last through breastfeeding.
The exception: If you’re taking levothyroxine for hypothyroidism, you don’t need iodine supplements.
Inexplicably, a large number of prescription and over-the-counter prenatal vitamins don’t contain any iodine, so be sure to check labels carefully. In the ones that do, the iodine is usually from either kelp or potassium iodide. Since the amount of iodine in kelp can vary so much, choose supplements made with potassium iodide.
Iodine’s Role in Thyroid Health
A Word From Verywell
While thyroid disease can affect your ability to get pregnant and your pregnancy itself, having a child can also give rise to postpartum thyroiditis. It’s important that you continue to have your thyroid monitored closely after pregnancy to ensure that you are being properly managed.
An Overview of Postpartum Thyroiditis
Complications of untreated hypothyroidism in pregnancy include the potential for miscarriage, stillbirth, preterm labor, and developmental problems affecting the child.
In most cases, yes. A study of 81 pregnant cisgender women with well-controlled hypothyroidism found that 84% needed an increase in their dosage, usually during the first trimester.The American Thyroid Association recommends that people with hypothyroidism should receive an adjusted dose of thyroid hormone replacement medication from a healthcare provider before getting pregnant.
Causes of hypothyroidism (underactive thyroid) can include Hashimoto’s disease, radiation treatment, a congenital issue, thyroiditis (inflammation of thyroid gland), certain medications, iodine deficiency, and more.
Learn MoreDifferences Between Hypothyroidism and Hyperthyroidism
11 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Alexander EK, Pearce EN, Brent GA, et al.2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.Thyroid. 2017;27(3):315-389. doi:10.1089/thy.2016.0457Jefferys A, Vanderpump M, Yasmin E.Thyroid dysfunction and reproductive health.The Obstetrician & Gynaecologist. 2015;17(1):39-45. doi:10.1111/tog.12161Mesen TB, Young SL.Progesterone and the Luteal Phase.Obstetrics and Gynecology Clinics of North America. 2015;42(1):135-151. doi:10.1016/j.ogc.2014.10.003.Gold EB.The timing of the age at which natural menopause occurs.Obstet Gynecol Clin North Am. 2011;38(3):425–440. doi:10.1016/j.ogc.2011.05.002Taylor PN, Minassian C, Rehman A, et al.TSH Levels and Risk of Miscarriage in Women on Long-Term Levothyroxine: A Community-Based Study.The Journal of Clinical Endocrinology & Metabolism. 2014;99(10):3895-3902. doi:10.1210/jc.2014-1954.Marx H, Amin P, Lazarus JH.Hyperthyroidism and pregnancy.BMJ. 2008;336(7645):663–667. doi:10.1136/bmj.39462.709005.AELi X, Liu GY, Ma JL, Zhou L.Risk of congenital anomalies associated with antithyroid treatment during pregnancy: a meta-analysis.Clinics (Sao Paulo). 2015;70(6):453–459. doi:10.6061/clinics/2015(06)12Zimmermann MB.Iodine deficiency in pregnancy and the effects of maternal iodine supplementation on the offspring: a review.The American Journal of Clinical Nutrition. 2008;89(2). doi:10.3945/ajcn.2008.26811c.American Thyroid Association.Iodine Daily Serving now recommended in Multivitamin/Mineral Supplements for Pregnant and Lactating Women.Kashi Z, Bahar A, Akha O, Hassanzade S, Esmaeilisaraji L, Hamzehgardeshi Z.Levothyroxine dosage requirement during pregnancy in well-controlled hypothyroid women: A longitudinal study.Glob J Health Sci. 2015;8(4):227-233. doi:10.5539/gjhs.v8n4p227Cleveland Clinic.Thyroid Disease.
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Alexander EK, Pearce EN, Brent GA, et al.2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.Thyroid. 2017;27(3):315-389. doi:10.1089/thy.2016.0457Jefferys A, Vanderpump M, Yasmin E.Thyroid dysfunction and reproductive health.The Obstetrician & Gynaecologist. 2015;17(1):39-45. doi:10.1111/tog.12161Mesen TB, Young SL.Progesterone and the Luteal Phase.Obstetrics and Gynecology Clinics of North America. 2015;42(1):135-151. doi:10.1016/j.ogc.2014.10.003.Gold EB.The timing of the age at which natural menopause occurs.Obstet Gynecol Clin North Am. 2011;38(3):425–440. doi:10.1016/j.ogc.2011.05.002Taylor PN, Minassian C, Rehman A, et al.TSH Levels and Risk of Miscarriage in Women on Long-Term Levothyroxine: A Community-Based Study.The Journal of Clinical Endocrinology & Metabolism. 2014;99(10):3895-3902. doi:10.1210/jc.2014-1954.Marx H, Amin P, Lazarus JH.Hyperthyroidism and pregnancy.BMJ. 2008;336(7645):663–667. doi:10.1136/bmj.39462.709005.AELi X, Liu GY, Ma JL, Zhou L.Risk of congenital anomalies associated with antithyroid treatment during pregnancy: a meta-analysis.Clinics (Sao Paulo). 2015;70(6):453–459. doi:10.6061/clinics/2015(06)12Zimmermann MB.Iodine deficiency in pregnancy and the effects of maternal iodine supplementation on the offspring: a review.The American Journal of Clinical Nutrition. 2008;89(2). doi:10.3945/ajcn.2008.26811c.American Thyroid Association.Iodine Daily Serving now recommended in Multivitamin/Mineral Supplements for Pregnant and Lactating Women.Kashi Z, Bahar A, Akha O, Hassanzade S, Esmaeilisaraji L, Hamzehgardeshi Z.Levothyroxine dosage requirement during pregnancy in well-controlled hypothyroid women: A longitudinal study.Glob J Health Sci. 2015;8(4):227-233. doi:10.5539/gjhs.v8n4p227Cleveland Clinic.Thyroid Disease.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Alexander EK, Pearce EN, Brent GA, et al.2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.Thyroid. 2017;27(3):315-389. doi:10.1089/thy.2016.0457Jefferys A, Vanderpump M, Yasmin E.Thyroid dysfunction and reproductive health.The Obstetrician & Gynaecologist. 2015;17(1):39-45. doi:10.1111/tog.12161Mesen TB, Young SL.Progesterone and the Luteal Phase.Obstetrics and Gynecology Clinics of North America. 2015;42(1):135-151. doi:10.1016/j.ogc.2014.10.003.Gold EB.The timing of the age at which natural menopause occurs.Obstet Gynecol Clin North Am. 2011;38(3):425–440. doi:10.1016/j.ogc.2011.05.002Taylor PN, Minassian C, Rehman A, et al.TSH Levels and Risk of Miscarriage in Women on Long-Term Levothyroxine: A Community-Based Study.The Journal of Clinical Endocrinology & Metabolism. 2014;99(10):3895-3902. doi:10.1210/jc.2014-1954.Marx H, Amin P, Lazarus JH.Hyperthyroidism and pregnancy.BMJ. 2008;336(7645):663–667. doi:10.1136/bmj.39462.709005.AELi X, Liu GY, Ma JL, Zhou L.Risk of congenital anomalies associated with antithyroid treatment during pregnancy: a meta-analysis.Clinics (Sao Paulo). 2015;70(6):453–459. doi:10.6061/clinics/2015(06)12Zimmermann MB.Iodine deficiency in pregnancy and the effects of maternal iodine supplementation on the offspring: a review.The American Journal of Clinical Nutrition. 2008;89(2). doi:10.3945/ajcn.2008.26811c.American Thyroid Association.Iodine Daily Serving now recommended in Multivitamin/Mineral Supplements for Pregnant and Lactating Women.Kashi Z, Bahar A, Akha O, Hassanzade S, Esmaeilisaraji L, Hamzehgardeshi Z.Levothyroxine dosage requirement during pregnancy in well-controlled hypothyroid women: A longitudinal study.Glob J Health Sci. 2015;8(4):227-233. doi:10.5539/gjhs.v8n4p227Cleveland Clinic.Thyroid Disease.
Alexander EK, Pearce EN, Brent GA, et al.2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.Thyroid. 2017;27(3):315-389. doi:10.1089/thy.2016.0457
Jefferys A, Vanderpump M, Yasmin E.Thyroid dysfunction and reproductive health.The Obstetrician & Gynaecologist. 2015;17(1):39-45. doi:10.1111/tog.12161
Mesen TB, Young SL.Progesterone and the Luteal Phase.Obstetrics and Gynecology Clinics of North America. 2015;42(1):135-151. doi:10.1016/j.ogc.2014.10.003.
Gold EB.The timing of the age at which natural menopause occurs.Obstet Gynecol Clin North Am. 2011;38(3):425–440. doi:10.1016/j.ogc.2011.05.002
Taylor PN, Minassian C, Rehman A, et al.TSH Levels and Risk of Miscarriage in Women on Long-Term Levothyroxine: A Community-Based Study.The Journal of Clinical Endocrinology & Metabolism. 2014;99(10):3895-3902. doi:10.1210/jc.2014-1954.
Marx H, Amin P, Lazarus JH.Hyperthyroidism and pregnancy.BMJ. 2008;336(7645):663–667. doi:10.1136/bmj.39462.709005.AE
Li X, Liu GY, Ma JL, Zhou L.Risk of congenital anomalies associated with antithyroid treatment during pregnancy: a meta-analysis.Clinics (Sao Paulo). 2015;70(6):453–459. doi:10.6061/clinics/2015(06)12
Zimmermann MB.Iodine deficiency in pregnancy and the effects of maternal iodine supplementation on the offspring: a review.The American Journal of Clinical Nutrition. 2008;89(2). doi:10.3945/ajcn.2008.26811c.
American Thyroid Association.Iodine Daily Serving now recommended in Multivitamin/Mineral Supplements for Pregnant and Lactating Women.
Kashi Z, Bahar A, Akha O, Hassanzade S, Esmaeilisaraji L, Hamzehgardeshi Z.Levothyroxine dosage requirement during pregnancy in well-controlled hypothyroid women: A longitudinal study.Glob J Health Sci. 2015;8(4):227-233. doi:10.5539/gjhs.v8n4p227
Cleveland Clinic.Thyroid Disease.
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