Purpose

We aimed to perform a systematic review and meta-analysis addressing the efficacy of levothyroxine therapy in pregnant women with subclinical hypothyroidism considering most recent evidence and subgroups of interest for clinical practice.

Methods

PubMed, Embase, and Cochrane Central were searched from inception for randomized controlled trials (RCTs) comparing levothyroxine with placebo or no intervention in pregnant women with subclinical hypothyroidism. We used a random-effects model and conducted subgroup analyses based on thyroid peroxidase antibody status, thyroid stimulating hormone levels, fertility treatment, and recurrent miscarriage.

Results

We included 11 RCTs comprising 2,749 pregnant women with subclinical hypothyroidism. Patients treated with levothyroxine (1,439; 52.3%) had significantly lower risk of pregnancy loss (risk ratio 0.69; 95% confidence interval 0.52–0.91; p < 0.01; 6 studies). However, there was no significant association between levothyroxine and live birth (risk ratio 1.01; 95% confidence interval 0.99–1.03; p = 0.29; 8 studies). No statistically significant interaction was observed across subgroups (p > 0.05).

Conclusion

Levothyroxine replacement therapy for subclinical hypothyroidism during pregnancy may decrease pregnancy loss when early prescribed. Nevertheless, further investigation is needed in patients with thyroid stimulating hormone above four milliunits per liter, especially when associated with recurrent miscarriage or infertility.

中文翻译：

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左旋甲状腺素治疗妊娠期亚临床甲状腺功能减退症：随机对照试验的最新系统评价和荟萃分析

目的

我们的目的是考虑最新的证据和临床实践中感兴趣的亚组，针对左甲状腺素治疗亚临床甲状腺功能减退症孕妇的疗效进行系统评价和荟萃分析。

方法

从一开始就搜索了 PubMed、Embase 和 Cochrane Central 的随机对照试验 (RCT)，比较左旋甲状腺素与安慰剂或不干预亚临床甲状腺功能减退症孕妇的情况。我们使用随机效应模型，并根据甲状腺过氧化物酶抗体状态、促甲状腺激素水平、生育治疗和复发性流产进行亚组分析。

结果

我们纳入了 11 项随机对照试验，其中包括 2,749 名患有亚临床甲状腺功能减退症的孕妇。接受左旋甲状腺素治疗的患者（1,439；52.3%）的流产风险显着降低（风险比 0.69；95% 置信区间 0.52–0.91；p  < 0.01；6 项研究）。然而，左旋甲状腺素与活产之间没有显着关联（风险比 1.01；95% 置信区间 0.99–1.03；p  = 0.29；8 项研究）。各亚组之间没有观察到统计学上显着的交互作用 ( p  > 0.05)。

结论

早期服用左旋甲状腺素替代疗法治疗妊娠期亚临床甲状腺功能减退症可能会减少流产。然而，对于促甲状腺激素超过每升四毫单位的患者，尤其是与反复流产或不孕相关的患者，还需要进一步研究。