A Meta-Analysis Examining the Impact of Levothyroxine Supplementation on Gestational Weight Gain in Women with Overt Hypothyroidism.

Background: Overt Hypothyroidism (OH) is commonly treated with Levothyroxine (LT4), typically at a dose of 50 to 100 mg per day. Hypothyroidism is associated with excessive weight gain; therefore, we meta-analyzed the effect of Materials and Methods: We conducted a comprehensive review of several databases, including Medline, Science Direct, ProQuest, Scopus, Web of Science, and the Cochrane Library, as well as Google Scholar. Our goal was to identify English-language Randomized Controlled Trials (RCTs) and observational studies assessing the impact of LT4 on GWG and Body Mass Index (BMI) in pregnant women with OH, between August 4 and January 30, 2023. Additionally, we explored Persian databases such as Magiran, Islamic World Science Citation (ISC), and Scientific Information Database (SID). Because the studies reviewed included participants with Subclinical Hypothyroidism (SCH) as well, the meta-analysis also incorporated data from individuals with both OH and SCH. Results: The random-effects model indicated that after LT4 therapy, the GWG was not significantly different between the treated and control groups in studies involving women with OH [mean = 0.04, 95% CI: (-0.64, 0.72), Conclusions: Following LT4 treatment in pregnant women diagnosed with hypothyroidism, there was no significant difference in total GWG between the treated and control counterparts.