Subclinical Hypothyroidism During Pregnancy: The Melbourne Public Hospitals Consensus.

Abstract

Interest in potential adverse outcomes associated with maternal subclinical hypothyroidism (normal Free T4, elevated TSH) has increased significantly over recent years. In turn, the frequency of maternal thyroid function testing has risen, despite universal thyroid function screening not being recommended, leading to a marked increase in referrals to obstetric endocrinology clinics. In 2017 the American Thyroid Association (ATA) revised their diagnostic and management guidelines. While welcome, these new guidelines contain recommendations which may cause confusion in clinical practice. To ensure uniform practice in the diagnosis and management of subclinical hypothyroidism in pregnancy across all Melbourne Public Hospitals. Consensus was achieved and the guidelines were endorsed by the Council of the Endocrine Society of Australia. Trimester and assay specific TSH reference intervals derived from healthy local populations should be used, where available. When unavailable, a TSH cut-off of 4 mU/L (replacing the previously recommended 2.5 mU/L) should be used to initiate treatment, irrespective of thyroid autoantibody status. The recommended starting dose of levothyroxine is 50 ug daily, with a therapeutic TSH target of 0.1 mU/L to 2.5 mU/L. Levothyroxine should generally be ceased after delivery, with some exceptions. Hospitals will ensure smooth transfer of care back to the woman's general practitioner with clear documentation of pregnancy thyroid management and a recommended plan for follow-up. Fewer women will be classified as having subclinical hypothyroidism during pregnancy, which is likely to lead to reductions in emotional stress, hospital visits, repeated blood tests and financial costs. Uniform clinical practice will occur across Melbourne. This article is protected by copyright. All rights reserved.