New guidelines on thyroid disease in pregnancy issued

Stagnaro-Green A. Thyroid. 2011;doi:10.1089/thy.2011.0087.

Based on the availability of new and ongoing research, the American Thyroid Association recently published recommendations for the diagnosis and management of thyroid disease during pregnancy and postpartum.

Previous studies already associated overt hypothyroidism and hyperthyroidism with negative effects in pregnant women, but current studies are now examining the relationship between subclinical hypothyroidism and potential adverse events such as miscarriage and preterm delivery, as well as postpartum thyroiditis.

Alex Stagnaro-Green, MD, chairman of the international task force charged with developing the recommendations, said he hoped that the guidelines will create “a greater understanding by clinicians and patients about the detrimental impact of thyroid disease during pregnancy and the importance of appropriate diagnosis and treatment.

“In the new guidelines, there will be a marked expansion of women who are screened for thyroid disease and more women with thyroid disease who will be treated,” Stagnaro-Green, who is also senior associate dean of education at the George Washington University School of Medicine and Health Sciences, told Endocrine Today. “Also, women with pre-existing hypothyroidism will be treated more aggressively prior to pregnancy.”

For instance, one important update recommends that all women aged 30 years and older be screened for thyroid disease during the first trimester. In addition, all women with a thyroid-stimulating hormone of more than 2.5 mU/L during the first trimester who are thyroid antibody positive should receive levothyroxine. Further, the task force states that levothyroxine dosing should be adjusted in women with hypothyroidism before becoming pregnant so as to achieve a TSH of less than 2.5 mU/L. The guidelines also recommend that, for women with Graves’ disease, the goal of antithyroid medication therapy should be a serum free thyroxine at or moderately higher than the normal reference range. Although not a new recommendation, Stagnaro-Green said it is important to take a prenatal vitamin that contains 150 mcg of iodine daily.

The task force outlined areas for future research, such as the cost-effectiveness of screening; the effects of iodine supplementation during pregnancy and lactation; safe upper limits for iodine ingestion; optimal targeted free T₄ levels in women with Graves’ disease; levothyroxine use in euthyroid patients who are thyroid peroxidase antibody positive for prevention of spontaneous abortion and preterm delivery; and the effect of levothyroxine therapy in euthyroid women with recurrent spontaneous abortion who are thyroid antibody positive.

“Thyroid disease during pregnancy is associated with miscarriage, preterm delivery and other negative outcomes in both the mother and the fetus,” Stagnaro-Green said. “All women with thyroid disease who are planning to become pregnant should see their physician prior to becoming pregnant to optimize treatment.” – by Melissa Foster

Disclosure: Dr. Stagnaro-Green and all task force members report no relevant financial disclosures.

Richard J. Robbins

The new ATA guidelines for managing and treating thyroid disorders before, during and following pregnancy are balanced and comprehensive. An international team of experts have taken on this vast issue that is reflected on 44 pages in the October issue of Thyroid. The effects of insufficient thyroid hormone on the pregnancy and on the developing fetus are well documented, and all practitioners should be screening for hypothyroidism in the high-risk group.

The guidelines address reference ranges for TSH and free thyroxine, targets to aim for with replacement thyroxine and adjustments that should be made in those who are already on thyroxine supplements. The issue of whether or not to treat subclinical hypothyroidism is less clear, although erring on the side of appropriate replacement has minimal risk. These guidelines also contain dissenting comments on controversial topics, which is refreshing and informative. The recommendation that all women planning pregnancy, or who are pregnant or breastfeeding, should take an additional 150 mcg of iodine daily seems well based on epidemiologic data. Supplemental iodine in excess of 500 mcg per day should be avoided. Guidelines for the treatment of hyperthyroidism and differentiated thyroid carcinoma in pregnancy incorporate the most recent data and are very reasonable. The importance of awareness of post-partum thyroiditis that may present either with hyper- or hypothyroidism is addressed. Overall, this is an authoritative and practical set of guidelines that deserved reading by all clinicians who care for women of childbearing age.

– Richard J. Robbins, MD
Endocrine Today Editorial Board member

Disclosure: Dr. Robbins reports no relevant financial disclosures.

The new guidelines on management of thyroid disease in pregnancy are evidence-based and in line with current practices of many obstetricians, although some organizations have not yet endorsed screening for hypothyroidism in pregnancy. I believe the guidelines will lead to better outcomes of pregnancy. Just yesterday I looked at three multivitamins for pregnancy and found that none of them contained iodine. The guidelines will provide motivation for changing this poor pharmaceutical practice.

– Jerome M. Hershman, MD
Endocrine Today Editorial Board member

Disclosure: Dr. Hershman reports no relevant financial disclosures.

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