Objective: Thyroid dysfunction affects up to 5–7% of all pregnancies. The rates of thyroid hormone use in nonpregnant population have substantially increased in recent years. The aim of this study was to assess possible changes in the use of levothyroxine substitution and antithyroid drugs over time in pregnant women. Methods: The study data consisted of all singleton pregnancies (N = 736,873) between 2004 and 2016 in Finland collected from the Finnish Medical Birth Register. The Prescription Register and Special Refund Entitlement Register provided information on levothyroxine and antithyroid drug purchases. The annual rates of levothyroxine and antithyroid drug prescription redemptions were explored to estimate changes in exposure rates to thyroid medication from 2004 to 2016. Joinpoint regression analyses were performed to explore interannual variability in levothyroxine and antithyroid drug treatment. Results: There was more than a five-fold increase in levothyroxine use during the study period; in 2004, 1.1% of pregnant women had levothyroxine treatment, and by 2016, the prevalence increased to 6.2%. In addition, we observed a slight increase in antithyroid medication during pregnancy, but antithyroid drug use during pregnancy overall was very rare. In 2004, 0.05% of pregnant women used antithyroid drugs, and by 2016, this percentage had increased to 0.14%. Conclusions: Our study shows that the rate of levothyroxine use in pregnancy has markedly increased. This suggests that tracing and screening relevant patients and awareness of thyroid disorders on pregnancy and their significance for the pregnancy outcome have increased and the threshold to treat thyroid disorders has declined.
Eur Thyroid J

中文翻译：

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妊娠期甲状腺疾病药物治疗的增加趋势：一项为期 13 年的全国研究

目标：甲状腺功能障碍影响多达 5-7% 的妊娠。近年来，非妊娠人群中甲状腺激素的使用率大幅增加。本研究的目的是评估孕妇使用左旋甲状腺素替代和抗甲状腺药物随时间可能发生的变化。方法：研究数据包括所有单胎妊娠（ N= 736,873) 2004 年至 2016 年间在芬兰从芬兰医疗出生登记处收集。处方登记册和特殊退款权利登记册提供了有关左旋甲状腺素和抗甲状腺药物购买的信息。研究了左旋甲状腺素和抗甲状腺药物处方赎回的年率，以估计 2004 年至 2016 年甲状腺药物暴露率的变化。进行了联合点回归分析，以探索左旋甲状腺素和抗甲状腺药物治疗的年际变化。结果：在研究期间左旋甲状腺素的使用增加了五倍以上；2004年，1.1%的孕妇接受过左旋甲状腺素治疗，到2016年，患病率上升到6.2%。此外，我们观察到怀孕期间抗甲状腺药物的使用略有增加，但总体而言，怀孕期间使用抗甲状腺药物的情况非常罕见。2004年，0.05%的孕妇使用抗甲状腺药物，到2016年，这一比例上升到0.14%。结论：我们的研究表明，妊娠期左旋甲状腺素的使用率显着增加。这表明对相关患者的追踪和筛查以及甲状腺疾病对妊娠的认识及其对妊娠结局的意义有所提高，治疗甲状腺疾病的门槛有所下降。
欧洲甲状腺杂志