Effects of Levothyroxine Treatment on Fertility and Pregnancy Outcomes in Subclinical Hypothyroidism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Akiko Sankoda, Hitomi Suzuki, Misa Imaizumi, Ai Yoshihara, Sakiko Kobayashi, Miyuki Katai, Katsuhiko Hamada, Yoh Hidaka, Aya Yoshihara, H Nakamura, Sumihisa Kubota, Maiko Kakita‐Kobayashi, Akira Iwase, Takashi Sugiyama, Erika Ota, Naoko Arata
Abstract
Background: Subclinical hypothyroidism, defined by elevated thyrotropin (TSH) and normal free thyroxine levels, is associated with adverse pregnancy outcomes, including preterm birth, pre-eclampsia, and small for gestational age. Despite the uncertainty regarding the effectiveness of levothyroxine (LT4) treatment on pregnancy outcomes in subclinical hypothyroidism, LT4 is widely administered with a pre-treatment threshold TSH level of 2.5 mU/L. The aim of this study is to investigate the efficacy of periconceptional LT4 treatment for subclinical hypothyroidism, including TSH levels >2.5 mU/L, and identify the characteristics of subclinical hypothyroidism that can benefit from LT4 treatment.