Care of Women with Thyroid Disease: Guideline Update

Abstract

Problem Statement: Endocrinology guidelines for the diagnosis and management of thyroid disease differ in pregnancy and postpartum compared to the preconception state. Aim: NPs need to be aware of the management updates within the 2017 American Thyroid Association Guidelines. Hypothyroidism is second only to diabetes in endocrine disorders in pregnancy. Background: Due to the structural similarities of hCG to TSH and the increase in thyroxine binding globulin during pregnancy, nurse practitioners should understand the relative physiologic changes. These changes result in varied interpretation of free T4 values, forcing clarification in thyroid hormone laboratory assays. Population: Women across the lifespan were assessed for the impact of thyroid disease within the following conditions; infertility, iodine deficiency, autoimmunity, subclinical disease, pregnancy complications, medications, and lactation. Evaluation: RCTs and primary studies were reviewed by national and international specialists with expertise in endocrine, obstetrics, and maternal-fetal medicine. Results: The new guidelines have been expanded to include lactation, infertility, and assisted reproductive techniques. Laboratory specific pregnancy TSH as well as free T4 trimester-specific ranges are suggested. If the latter are not available, a total T4 may be monitored. According to the revised guidelines, if the TSH is 2.5-10.0mU/L, a reflex TPOAb test is now obtained rather than a reflex free T4. Upon confirmation of pregnancy, those with an established diagnosis of overt hypothyroidism, the LT4 supplementation is increased 20-30%, e.g. an additional two doses per week. This decreases the risk of premature birth and low birth weight. For women with a history of radioiodine treatment, conception should be planned after a six-month minimum to allow for stability of hormonal thyroid levels. Early postpartum follow-up for thyroiditis is essential not only for those with type 1 diabetes mellitus but also those with positive thyroid antibodies (TPOAb). Postpartum symptoms can include irritability, heat intolerance, and palpitations. Furthermore, allergies or sensitivities may affect the bioavailability of a generic thyroid medication, and subsequently a trade brand thyroid may be indicated. Conclusions: Important adjustments of thyroid supplementation are now more defined within pregnancy, assisting with clinical decision-making, and ultimately improving pregnancy outcomes relative to preterm birth and low birth weight.