Objective To explore the effect of L-T4 treatment on pregnancy outcome and the change of TSH in TPO-Ab-negative patients associated with subclinical hypothyroidism( SCH) during pregnancy. Methods From 2014 to 2015,84 TPO-Ab-negative patients associated with SCH,who were confirmed by pregnancy diagnosis and had childbirth,were enrolled as study subjects in the retrospective analysis. Patients were divided into treatment group( voluntarily receiving L-T4 standard treatment,n = 39) and control group( receiving...