Sun X, et al. - In view of the correlation of thyroid autoimmunity (TAI), the most common cause of (sub)clinical hypothyroidism, with adverse pregnancy outcomes, researchers here examined how levothyroxine (LT4) influences pregnancy outcomes in euthyroid women with TAI. Searching databases up to May 2019, inclusion of six trials involving 2,249 women was done. The analysis yielded no definitive evidence indicative of improvement of pregnancy outcomes with LT4 supplementation in euthyroid women with TAI. However, there may be a great importance of therapeutic strategies, particularly dosages and initial times of intervention. Decrease in the risk of miscarriage was observed for women with individualized initial LT4 dosages. Further, there was a significantly lower preterm birth rate among women who started LT4 treatment in early pregnancy.