Leslie J. De Groot

OBJECTIVE: The aim was to update the guidelines for the management of thyroid dysfunction during pregnancy and postpartum published previously in 2007. A summary of changes between the 2007 and 2012 version is identified in the Supplemental Data (published on The Endocrine Society's Journals Online web site at http://jcem.endojournals.org). EVIDENCE: This evidence-based guideline was developed according to the U.S. Preventive Service Task Force, grading items level A, B, C, D, or I, on the basis of the strength of evidence and magnitude of net benefit (benefits minus harms) as well as the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence. CONSENSUS PROCESS: The guideline was developed through a series of e-mails, conference calls, and one face-to-face meeting. An initial draft was prepared by the Task Force, with the help of a medical writer, and reviewed and commented on by members of The Endocrine Society, Asia and Oceania Thyroid Association, and the Latin American Thyroid Society. A second draft was reviewed and approved by The Endocrine Society Council. At each stage of review, the Task Force received written comments and incorporated substantive changes. CONCLUSIONS: Practice guidelines are presented for diagnosis and treatment of patients with thyroid-related medical issues just before and during pregnancy and in the postpartum interval. These include evidence-based approaches to assessing the cause of the condition, treating it, and managing hypothyroidism, hyperthyroidism, gestational hyperthyroidism, thyroid autoimmunity, thyroid tumors, iodine nutrition, postpartum thyroiditis, and screening for thyroid disease. Indications and side effects of therapeutic agents used in treatment are also presented.

OBJECTIVE: The objective is to provide clinical guidelines for the management of thyroid problems present during pregnancy and in the postpartum. PARTICIPANTS: The Chair was selected by the Clinical Guidelines Subcommittee (CGS) of The Endocrine Society. The Chair requested participation by the Latin American Thyroid Society, the Asia and Oceania Thyroid Society, the American Thyroid Association, the European Thyroid Association, and the American Association of Clinical Endocrinologists, and each organization appointed a member to the task force. Two members of The Endocrine Society were also asked to participate. The group worked on the guidelines for 2 yr and held two meetings. There was no corporate funding, and no members received remuneration. EVIDENCE: Applicable published and peer-reviewed literature of the last two decades was reviewed, with a concentration on original investigations. The grading of evidence was done using the United States Preventive Services Task Force system and, where possible, the GRADE system. CONSENSUS PROCESS: Consensus was achieved through conference calls, two group meetings, and exchange of many drafts by E-mail. The manuscript was reviewed concurrently by the Society's CGS, Clinical Affairs Committee, members of The Endocrine Society, and members of each of the collaborating societies. Many valuable suggestions were received and incorporated into the final document. Each of the societies endorsed the guidelines. CONCLUSIONS: Management of thyroid diseases during pregnancy requires special considerations because pregnancy induces major changes in thyroid function, and maternal thyroid disease can have adverse effects on the pregnancy and the fetus. Care requires coordination among several healthcare professionals. Avoiding maternal (and fetal) hypothyroidism is of major importance because of potential damage to fetal neural development, an increased incidence of miscarriage, and preterm delivery. Maternal hyperthyroidism and its treatment may be accompanied by coincident problems in fetal thyroid function. Autoimmune thyroid disease is associated with both increased rates of miscarriage, for which the appropriate medical response is uncertain at this time, and postpartum thyroiditis. Fine-needle aspiration cytology should be performed for dominant thyroid nodules discovered in pregnancy. Radioactive isotopes must be avoided during pregnancy and lactation. Universal screening of pregnant women for thyroid disease is not yet supported by adequate studies, but case finding targeted to specific groups of patients who are at increased risk is strongly supported.

For more than 3 decades it has been known that serum thyroid hormone levels drop during starvation and illness. In mild illness, this involves only a decrease in serum T3 levels. However, as the severity of the illness increases, there is a drop in both serum T3 and T4 (1). This decrease in serum thyroid hormone levels is seen in starvation (2), sepsis (3, 4), surgery (5), myocardial infarction (6, 7), bypass (8), bone marrow transplantation (9), and, in fact, probably any severe illness. Based on the conviction that patients with these abnormalities are not hypothyroid despite the low hormone levels in blood, the condition has been called the euthyroid sick syndrome. An alternative designation, which does not presume the metabolic status of the patient, is nonthyroidal illness syndrome (NTIS). NTIS seems a preferable name in light of present knowledge and will be used in this review.

To determine wether the occurrence of x-ray-induced thyroid carcinoma has not declined, we examined 100 patients with a history of irradiation to the neck area. Irradiation had been given to tonsils (42 per cent), adenoids (10 per cent), tonsils and adenoids (7 per cent) and thymus (30 per cent), for acne (7 per cent), and for various other reasons (7 per cent). Operation was recommended to 18 of 26 patients with palpable abnormalities and 15 were operated upon; we found seven carcinomas, and eight benign lesions. Five of six carcinomas had invasive characteristics, with or without metastases, five of seven were multifocal, and six of seven had a follicular component. Of seven patients irradiated to both tonsils and adenoids and thus receiving higher radiation exposure, two had carcinoma, suggesting a dose relation. The overall 7 per cent prevalence of carcinoma in unselected patients with a history of irradiation to the neck area is higher than expected and implies a continuing important public-health problem, at least in the Chicago area. (N Engl J Med 292:171–175, 1975)