What are the guideline sources, guidelines and references for Thyroid disease in pregnancy ?
Guideline sources The following summarized guidelines for the evaluation and management of thyroid disease in pregnancy are prepared by our editorial team based on guidelines from the American College of Obstetricians and Gynecologists (ACOG 2020) and the American Thyroid Association (ATA 2017). 1 2 Guidelines 1. Screening and diagnosis Indications for screening: As per ACOG 2020 guidelines: Do not obtain universal screening for thyroid disease in pregnancy because identification and treatment of maternal subclinical hypothyroidism has not been shown to result in improved pregnancy outcomes and neurocognitive function in offspring. D https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 1/8 6/24/23, 4:06 PM Thyroid disease in pregnancy Pathway Obtain TSH as first-line screening test to assess thyroid status, if indicated. A As per ATA 2017 guidelines, screen all pregnant women verbally at the initial prenatal visit for any history of thyroid dysfunction, and prior or current use of either thyroid hormone or antithyroid medications, such as methimazole, carbimazole, or propylthiouracil. A Show 3 more Indications for testing: As per ACOG 2020 guidelines: Obtain testing of thyroid function in patients with a personal or family history of thyroid disease, T1DM, or clinical suspicion of thyroid disease. B Do not obtain testing of thyroid function in patients with hyperemesis gravidarum unless other signs of overt hyperthyroidism are evident. D As per ATA 2017 guidelines: Obtain a serum thyroid stimulating hormone to test for thyroid dysfunction in patients who are seeking pregnancy or newly pregnant and in whom any of the following risk factors are identified: hhistory of hypothyroidism/hyperthyroidism or current symptoms/signs of thyroid dysfunction known thyroid antibody positivity or presence of a goitre history of head or neck radiation or prior thyroid surgery age > 30 years T1DM or other autoimmune disorder history of pregnancy loss, preterm delivery, or infertility multiple prior pregnancies ( 2) family history of autoimmune thyroid disease or thyroid dysfunction morbid obesity, as defined by a BMI 40 kg/m use of amiodarone or lithium, or recent administration of iodinated radiologic contrast residence in an area of known moderate-to-severe iodine insufficiency. B Screen all patients with depression, including postpartum depression, for thyroid dysfunction. B Diagnosis of hypothyroidism: diagnose maternal hypothyroidism in patients with a thyroid stimulating hormone concentration higher than the upper limit of the pregnancy-specific reference range. A 2. Diagnostic investigations Thyroid function tests: use trimester-specific reference ranges for serum thyroid stimulating hormone measurement in pregnant women. B Show 3 more TSH receptor antibodies: https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 2/8 6/24/23, 4:06 PM Thyroid disease in pregnancy Pathway Obtain a maternal serum determination of thyroid stimulating hormone receptor antibody at initial thyroid function testing during early pregnancy if the patient has a past history of Graves disease treated with ablation, either with radioactive iodine or surgery. B Obtain a maternal serum determination of thyroid stimulating hormone receptor antibody if a patient is taking antithyroid drugs for the treatment of Graves hyperthyroidism when pregnancy is confirmed. B Thyroid peroxidase antibodies: evaluate pregnant women with thyroid stimulating hormone concentrations > 2.5 mU/L for antibodies to thyroid peroxidase status. Serum calcitonin: recognize that the utility of measuring calcitonin in pregnant women with thyroid nodules is unknown. The task force cannot recommend for or against routine measurement of serum calcitonin in pregnant women with thyroid nodules. B Urine iodine concentration: consider using median urinary iodine concentrations to assess the iodine status of populations, but single spot or 24-hour urinary iodine concentrations are not a valid marker for the iodine nutritional status of individual patients. B Radionuclide scintigraphy: avoid obtaining radionuclide scintigraphy or radioactive iodine uptake determination during pregnancy. D Thyroid ultrasound: perform sonographic monitoring for pseudotumor cerebri detected in early pregnancy. Perform surgery during pregnancy if it grows substantially before 24-26 weeks gestation, or if cytologically malignant cervical lymph nodes are present. Consider deferring surgery until after delivery if the disease remains stable by midgestation, or if it is diagnosed in the second half of pregnancy. B Show 3 more 3. Diagnostic procedures Thyroid nodule biopsy: consider deferring fine needle aspirate of a clinically relevant thyroid nodule until after pregnancy, for women with suppressed serum thyroid stimulating hormone levels that persist beyond 16 weeks gestation. Consider obtaining a radionuclide scan, if not breastfeeding, to evaluate nodule function at that time, if serum thyroid stimulating hormone remains suppressed. B Show 4 more 4. Medical management Management of pre-existing hyperthyroidism: discuss the possibility of future pregnancy in all women of childbearing age who are thyrotoxic. Counsel women with Graves' disease seeking future pregnancy regarding the complexity of disease management during future gestation, including the association of birth defects with antithyroid drugs use. Review the risks and benefits of all treatment options and the patient's desired timeline to conception in the preconception counseling. A Show 6 more https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 3/8 6/24/23, 4:06 PM Thyroid disease in pregnancy Pathway Management of pre-existing hypothyroidism: counsel treated hypothyroid women of reproductive age regarding the likelihood of increased demand for levothyroxine during pregnancy. Counsel such women also on contacting their caregiver immediately upon a confirmed or suspected pregnancy. A Show 2 more Management of overt hyperthyroidism: Initiate antithyroid drugs (thioamides) in pregnant patients with overt hyperthyroidism. A Consider initiating either propylthiouracil or methimazole, both thioamides, in pregnant patients with overt hyperthyroidism depending on: trimester of pregnancy response to prior therapy thyrotoxicosis being predominantly T4 or T3. C Management of overt hypothyroidism: As per ACOG 2020 guidelines, initiate adequate thyroid hormone replacement in pregnant patients with overt hypothyroidism to minimize the risk of adverse outcomes. A As per ATA 2017 guidelines: Initiate levothyroxine treatment in patients with overt hypothyroidism during pregnancy. B Do not use thyroid preparations other than levothyroxine (such as T3 or desiccated thyroid) in pregnant patients. D Management of subclinical hypothyroidism: initiate levothyroxine therapy in women with subclinical hypothyroidism during pregnancy and a TSH > 10.0 mU/L. B Show 4 more Management of isolated hypothyroxinemia: avoid routine treatment for isolated hypothyroxinemia in pregnancy. D Management of isolated anti-TPO positivity: Insufficient evidence to support the use of levothyroxine to decrease pregnancy loss risk in newly pregnant euthyroid females with thyroid peroxidase antibodies. Consider initiating levothyroxine (at a starting dose of 25-50 g/day) in thyroid peroxidase antibody-positive euthyroid pregnant patients with a prior history of loss, given its potential benefits compared with its minimal risk. I Insufficient evidence to recommend for or against levothyroxine therapy to prevent preterm delivery in euthyroid pregnant females with thyroid autoantibodies. I Management of postpartum thyroiditis: consider treating symptomatic women with -blockers during the thyrotoxic phase of postpartum thyroiditis. Administer a -blocker that is safe for lactating women, such as propranolol or metoprolol, at the lowest possible dose to alleviate symptoms as the treatment of choice. Therapy is typically required for a few weeks. B Show 6 more Intravenous immunoglobulin: avoid IVIG treatment of euthyroid women with a history of recurrent pregnancy loss. D https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 4/8 6/24/23, 4:06 PM Thyroid disease in pregnancy Pathway Levothyroxine: administer levothyroxine treatment to infertile women with overt hypothyroidism who desire pregnancy. B Show 2 more Corticosteroid therapy: avoid administering corticosteroid therapy for thyroid autoantibody- positive euthyroid women undergoing assisted reproductive techniques. D 5. Nonpharmacologic interventions Dietary modifications: advise all prgnant women to take approximately 250 g iodine daily. Consider varying the stratigies based on country of origin to achieve a total of 250 g iodine ingestion daily. A Show 7 more Selenium supplementation: avoid selenium supplementation for the treatment of thyroid peroxidase antibody-positive women during pregnancy. D 6. Therapeutic procedures Radioactive iodine: advise deferring pregnancy for 6 months after a woman has received therapeutic radioactive iodine 131I treatment. B Cordocentesis: consider performing cordocentesis in selected, rare circumstances, such as when fetal goiter is detected in women taking antithyroid drugs, in order to help determine whether the fetus is hyperthyroid or hypothyroid. C 7. Perioperative care Pre-operative optimization: avoid any other preparation in the setting of a patient with Graves' disease undergoing urgent, non-thyroid surgery, if the patient is well controlled on antithyroid drugs. Administer -blockade if needed. D 8. Surgical interventions Thyroidectomy: consider performing thyroidectomy in pregnancy for unique scenarios. Recognize that if required, the optimal time for thyroidectomy is in the second trimester of pregnancy. Monitor the fetus carefully for development of fetal hyperthyroidism throughout pregnancy, if maternal thyroid stimulating hormone receptor concentration is high, such as > 3 times the upper reference for the assay, even if the mother is euthyroid post thyroidectomy. B 9. Specific circumstances https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 5/8 6/24/23, 4:06 PM Thyroid disease in pregnancy Pathway Patients undergoing controlled ovarian hyperstimulation: treat TSH elevations, in women who achieve pregnancy following controlled ovarian hyperstimulation, according to the recommendations outlined in Section VII. Repeat serum thyroid stimulating hormone measurements in 2-4 weeks in nonpregnant women with mild thyroid stimulating hormone elevations following controlled ovarian stimulation, because levels may normalize. B Patients who are thyroid antibody positive: measure serum thyroid stimulating hormone concentration in euthyroid pregnant women who are thyroid peroxidase antibody or thyroglobulin antibody positive, at time of pregnancy confirmation and every 4 weeks through midpregnancy. A Patients with infertility: measure serum thyroid stimulating hormone concentration in all women seeking care for infertility. B Show 2 more Patients with thyroid malignancy: Recognize that the impact of pregnancy on women with newly diagnosed medullary carcinoma or anaplastic cancer is unknown. However, a delay in treatment is likely to adversely affect outcome. Thererfore, think strongly about performing surgery, following assessment of all clinical factors. B Manage pregnant women with thyroid cancer at the same thyroid stimulating hormone goal as determined preconception. Monitor TSH approximately every 4 weeks until 16-20 weeks of gestation, and at least once between 26 and 32 weeks of gestation. B Newborn patients: screen all newborns for hypothyroidism by blood spot analysis typically 2-5 days after birth. A Show 3 more Lactating patients: avoid administration of Iodine-131 during lactation. Consider using Iodine-123 if required; if breast milk is pumped and discarded for 3-4 days before breastfeeding is resumed. Similarly, Technitium-99m pertechnetate administration requires breast milk to be pumped and discarded during the day of testing. D Show 5 more 10. Follow-up and surveillance Indications for specialist referral: Communicate a history of maternal thyroid illness, use of antithyroid medications (such as propylthiouracil, methimazole) during gestation, or measurements of abnormal maternal thyroid function or thyroid stimulating hormone receptor antibody during gestation, to the newborn's neonatologist or pediatrician. B Decide the timing of communication based on the severity of maternal and fetal thyroid illness. Recognize that severe, progressive, or complex thyroid illness during pregnancy mandates communication with the neonatologist or pediatrician before birth and consideration of consultation with a pediatric endocrinologist. Most other illness is optimally communicated shortly after birth. B https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 6/8 6/24/23, 4:06 PM Thyroid disease in pregnancy Pathway Indications for fetal surveillance: Perform fetal surveillance in women who have uncontrolled hyperthyroidism in the second half of pregnancy, and in women with high thyroid stimulating hormone receptor antibody levels, > 3 times the ULN, detected at any time during pregnancy. Organize a consultation with an experienced obstetrician or maternal-fetal medicine specialist. Consider obtaining ultrasound as a part of monitoring, to assess HR, growth, amniotic fluid volume, and the presence of fetal goiter. B Monitor the fetus carefully for goiter and signs of hypothyroidism during the second half of pregnancy, if antithyroid drug therapy is given for hyperthyroidism caused by autonomous nodules. Administer a low dose of antithyroid drug with the goal of maternal free thyroxine or total thyroxine concentration at the upper limit or moderately above the reference range. B Therapeutic targets (hypothyroidism): Consider targetting a thyroid stimulating hormone level in the lower half of the trimester-specific reference range in parallel to the treatment of hypothyroidism in a general population. Consider targetting maternal throid stimulating hormone concentrations < 2.5 milliunits/L when this is not available. C Obtain serum thyroid stimulating hormone measurement approximately every 4 weeks until midgestation and at least once near 30 weeks gestation in women with overt and subclinical hypothyroidism, treated or untreated, or those at risk for hypothyroidism (for example, patients who are euthyroid but thyroid peroxidase antibody or thyroglobulin antibody positive, post- hemithyroidectomy, or treated with radioactive iodine). A Therapeutic targets (hyperthyroidism): administer antithyroid medication during pregnancy at the lowest effective dose of methimazole or propylthiouracil, targeting maternal serum free thyroxine/total thyroxine at the upper limit or moderately above the reference range. A Serial thyroid function test measurement: As per ACOG 2020 guidelines: Monitor the level of TSH in pregnant patients being treated for hypothyroidism and adjust the dose of levothyroxine accordingly with a goal of TSH level between the lower limit of the reference range and 2.5 milliunits/L. Obtain TSH every 4-6 weeks while adjusting medications. A Monitor the level of free T4 in pregnant patients being treated for hyperthyroidism and adjust the dose of antithyroid drug (thioamide) accordingly to achieve a free T4 at the upper end of the normal pregnancy range. Monitor the level of total T3 in patients also having T3 thyrotoxicosis with a goal level at the upper end of normal pregnancy range. A As per ATA 2017 guidelines: Monitor the levels of free thyroxine, total thyroxine, and thyroid stimulating hormone approximately every 4 weeks, in women being treated with antithyroid drugs in pregnancy. B Avoid prescribing a combination regimen of levothyroxine and an antithyroid drug in pregnancy, except in the rare situation of isolated fetal hyperthyroidism. D Serial TSH receptor antibody measurement: avoid further TSH receptor antibody testing, if maternal TSH receptor antibody is undetectable or low in early pregnancy. D https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 7/8 6/24/23, 4:06 PM Thyroid disease in pregnancy Pathway Show 3 more Postpartum care: reduce levothyroxine to the patient's preconception dose, following delivery. Obtain additional thyroid function testing at approximately 6 weeks post partum. B Show 3 more References 1. Erik K Alexander, Elizabeth N Pearce, Gregory A Brent et al. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid. 2017 Mar;27 3 315 389. Open 2. No authors listed. Thyroid Disease in Pregnancy: ACOG Practice Bulletin, Number 223. Obstet Gynecol. 2020 Jun;135 6):e261-e274. Open 3. Ross DS, Burch HB, Cooper DS et al. 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis. Thyroid. 2016 Oct;26 10 1343 1421. Open https://web.pathway.md/diseases/rec2OsWuaWC5J9A9n 8/8