Yoshihara H, Sugiura‐Ogasawara M, Goto S, et al. - Since the connection between subclinical hypothyroidism (SCH) and recurrent pregnancy loss (RPL) remains uncertain, researchers conducted this observational cohort study to ascertain if SCH affects subsequent live births and if levothyroxine is effective in improving the live birth rate in patients with RPL. They involved 1,418 pregnancies of 1,014 patients with a history of 2 or more pregnancy losses, who were euthyroid or had hypothyroidism, and had at least one subsequent pregnancy outcome. Data reported that the prevalence of SCH was 14.4%. Live birth rates were 89.2%, 90.0% and 91.1% after excluding miscarriages with abnormal karyotypes. It was noted that the live birth rates per pregnancy, respectively, were 93.1%, 85.7%, and 90.9%. Levothyroxine has no effect on the improvement of the live birth rate in SCH-associated RPL patients. Treatment in patients with RPL and SCH raised TSH levels (2.5‐10mIU/L) may not be effective in improving the live birth rate.