Adequate thyroid hormone availability is important for an uncomplicated pregnancy and optimal fetal growth and development. Overt thyroid disease is associated with a wide range of adverse obstetric and child development outcomes. An increasing number of studies now indicate that milder forms of thyroid dysfunction are also associated with these adverse pregnancy outcomes. The definitions of both overt and subclinical thyroid dysfunction have changed considerably over the past few years, as new data indicate that the commonly used fixed upper limits of 2.5 mU/l or 3.0 mU/l for thyroid-stimulating hormone (TSH) are too low to define an abnormal thyroid function. Furthermore, some studies now show that the reference ranges are not necessarily the best cut-off for identifying pregnancies at high risk of adverse outcomes. In addition, data suggest that thyroid peroxidase autoantibody positivity and high or low concentrations of human chorionic gonadotropin seem to have a more prominent role in the interpretation of thyroid dysfunction than previously thought. Data on the effects of thyroid disease treatment are lacking, but some studies indicate that clinicians should be aware of the potential for overtreatment with levothyroxine. Here, we put studies from the past decade on reference ranges for TSH, determinants of thyroid dysfunction, risks of adverse outcomes and options for treatment into perspective. In addition, we provide an overview of the current views on thyroid physiology during pregnancy and discuss strategies to identify high-risk individuals who might benefit from levothyroxine treatment.

中文翻译：

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妊娠甲状腺疾病：诊断和临床管理的新见解

充足的甲状腺激素可用性对于不复杂的妊娠和最佳的胎儿生长发育至关重要。甲状腺疾病明显与多种不良产科和儿童发育结局有关。现在越来越多的研究表明，较轻形式的甲状腺功能障碍也与这些不良妊娠结局有关。在过去的几年中，明显的和亚临床甲状腺功能障碍的定义已经发生了很大变化，因为新数据表明，常用的甲状腺刺激激素（TSH）的固定上限2.5 mU / l或3.0 mU / l太低定义甲状腺功能异常。此外，现在的一些研究表明，参考范围不一定是确定具有不良后果高风险的妊娠的最佳分界点。此外，数据表明，甲状腺过氧化物酶自身抗体阳性和高或低浓度的人绒毛膜促性腺激素似乎在解释甲状腺功能障碍中比以前认为的更为重要。尚缺乏有关甲状腺疾病治疗效果的数据，但一些研究表明，临床医生应意识到用左甲状腺素过度治疗的可能性。在这里，我们将过去十年的研究针对TSH，甲状腺功能障碍的决定因素，不良结局风险和治疗选择的参考范围进行了研究。此外，我们提供了妊娠期甲状腺生理学当前观点的概述，并讨论了确定可能从左甲状腺素治疗中受益的高危人群的策略。