Bein Magnus, Yu Oriana Hoi Yun, Grandi Sonia Marzia, Frati Francesca Y E, Kandil Ihab, Filion Kristian B
Department of Biology, McGill University, Montreal, Quebec, Canada.
Department of Medicine, McGill University, Montreal, Quebec, Canada.
BMC Endocr Disord. 2021 Feb 27;21(1):34. doi: 10.1186/s12902-021-00699-5.
Levothyroxine replacement therapy may decrease the risk of adverse pregnancy outcomes among women with subclinical hypothyroidism (SCH). The aim of this study is to conduct a systematic review and meta-analysis to examine the risk of adverse pregnancy, perinatal, and early childhood outcomes among women with SCH treated with levothyroxine.
A systematic literature search was conducted using Ovid-Medline, Ovid-EMBASE, Pubmed (non-Medline), Ebsco-CINAHL Plus with full text and Cochrane Library databases. Randomized controlled studies (RCTs) and observational studies examining the association between treatment of SCH during pregnancy and our outcomes of interest were included. Studies that compared levothyroxine treatment versus no treatment were eligible for inclusion. Data from included studies were extracted and quality assessment was performed by two independent reviewers.
Seven RCTs and six observational studies met our inclusion criteria. A total of 7342 individuals were included in these studies. RCTs demonstrated several sources of bias, with lack of blinding of the participants or research personnel; only one study was fully blinded. In the observational studies, there was moderate to serious risk of bias due to lack of adjustment for certain confounding variables, participant selection, and selective reporting of results. Pooled analyses showed decreased risk of pregnancy loss (RR: 0.79; 95% CI: 0.67 to 0.93) and neonatal death (RR: 0.35; 95% CI: 0.17 to 0.72) associated with levothyroxine treatment during pregnancy among women with SCH. There were no associations between levothyroxine treatment and outcomes during labour and delivery, or cognitive status in children at 3 or 5 years of age.
Treatment of SCH with levothyroxine during pregnancy is associated with decreased risks of pregnancy loss and neonatal death. Given the paucity of available data and heterogeneity of included studies, additional studies are needed to address the benefits of levothyroxine use among pregnant women with SCH.
左甲状腺素替代疗法可能会降低亚临床甲状腺功能减退症（SCH）女性不良妊娠结局的风险。本研究的目的是进行一项系统评价和荟萃分析，以研究接受左甲状腺素治疗的SCH女性发生不良妊娠、围产期及儿童早期结局的风险。
使用Ovid - Medline、Ovid - EMBASE、Pubmed（非Medline）、Ebsco - CINAHL Plus全文数据库和Cochrane图书馆数据库进行系统的文献检索。纳入随机对照试验（RCT）和观察性研究，这些研究探讨了孕期SCH治疗与我们感兴趣的结局之间的关联。比较左甲状腺素治疗与未治疗的研究符合纳入标准。提取纳入研究的数据，并由两名独立的评审员进行质量评估。
七项RCT和六项观察性研究符合我们的纳入标准。这些研究共纳入7342人。RCT显示出多种偏倚来源，包括参与者或研究人员未设盲；只有一项研究完全设盲。在观察性研究中，由于未对某些混杂变量进行调整、参与者选择以及结果的选择性报告，存在中度至严重的偏倚风险。汇总分析显示，SCH女性孕期接受左甲状腺素治疗与流产风险降低（RR：0.79；95%CI：0.67至0.93）和新生儿死亡风险降低（RR：0.35；95%CI：0.17至0.72）相关。左甲状腺素治疗与分娩期间的结局或3岁或5岁儿童的认知状态之间无关联。
孕期用左甲状腺素治疗SCH与流产和新生儿死亡风险降低相关。鉴于现有数据匮乏且纳入研究存在异质性，需要更多研究来探讨左甲状腺素在SCH孕妇中的应用益处。
