Medical treatment in pregnant women with subclinical hypothyroidism: systematic review and meta-analysis

Abstract Objectives: to determine the effectiveness of medical therapy in reducing complications associated with subclinical hypothyroidism during pregnancy. Methods: in 2021, a systematic review of available cohort studies was carried out in three databases, with no publication date limit. Study selection and data extraction were performed in duplicate. Random-effects meta-analysis was performed, and odds ratios were calculated, with the corresponding 95% confidence intervals. Cohort risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). The certainty of the evidence was assessed using the GRADE methodology. Results: five studies were included for qualitative and quantitative synthesis. A statistically significant relationship was found between medical treatment in pregnant women with subclinical hypothyroidism with respect to spontaneous abortion (p=0.03; OR=0.77; CI95%=0.61-0.97), and no statistically significant relationship was found for delivery preterm (p=0.46; OR=1.11; CI95%=0.85-1.44), nor for abrupt placentae (p=0.56; OR=1.60; CI95%=0.33-7.66). Three studies were at moderate risk of bias, and two were at low risk of bias. In all the results the certainty was very low. Conclusions: medical treatment of subclinical hypothyroidism during pregnancy can have a beneficial effect in reducing cases of spontaneous abortion.摘要 研究目的：明确药物治疗在降低妊娠亚临床甲状腺功能减退症相关并发症方面的有效性。研究方法：2021年，本研究针对三个数据库中已有的队列研究开展系统综述，未设置发表日期限制。研究筛选与数据提取均由两名研究者独立重复完成。采用随机效应模型开展荟萃分析，计算比值比（odds ratios）及其对应的95%置信区间（95% confidence intervals）。采用纽卡斯尔-渥太华量表（Newcastle-Ottawa Scale, NOS）评估队列研究的偏倚风险，采用GRADE方法（Grading of Recommendations Assessment, Development and Evaluation）评估证据确定性。研究结果：共纳入5项研究进行定性与定量合成分析。结果显示，妊娠亚临床甲状腺功能减退症患者接受药物治疗与自然流产风险存在统计学显著相关性（p=0.03；OR=0.77；95%CI=0.61~0.97）；而针对早产（p=0.46；OR=1.11；95%CI=0.85~1.44）与胎盘早剥（p=0.56；OR=1.60；95%CI=0.33~7.66），未发现统计学显著相关性。其中3项研究存在中等偏倚风险，2项研究偏倚风险较低。所有研究结果的证据确定性均为极低级别。研究结论：妊娠期亚临床甲状腺功能减退症的药物治疗，可降低自然流产的发生风险，发挥有益作用。