Abstract
AIMS: The purpose of this study is to investigate the impact of subclinical hypothyroidism (SCH) during pregnancy and levothyroxine (LT4) therapy on pregnancy outcomes. METHODS: Among 6,510 pregnant women who came to The Fourth Hospital of Shijiazhuang for pregnancy examination and delivery, 266 pregnant women with SCH and treated with LT4 were selected as the SCH group and 672 pregnant women without SCH were selected as the non-SCH group, and the incidence rates of adverse pregnancy outcomes in pregnant women and newborns of the two groups were compared using Chi-square test and logistic regression. According to the therapeutic effect, pregnant women treated with LT4 were categorized into sustained euthyroid status (SES) and suboptimal thyroid status (STS) groups and compared with the non-SCH group using chi-square test. The correlation of thyroid stimulating hormone (TSH) levels at different stages of pregnancy was explored using Spearman's rank test. RESULTS: The incidence of hypertensive disorders of pregnancy (HDP), premature rupture of membranes (PROM), and neonatal outcomes were ventricular or atrial septal defect (V/ASD), hyperbilirubinemia, and pneumonia were higher in the SCH group (SCH pregnant women) than in the non-SCH group (non-SCH pregnant women) (p < 0.05). The incidence of multiple maternal and neonatal complications was higher in the SCH-STS group (SCH in two or three gestational trimesters) compared to the SCH group. With a tendency for TSH levels to increase as the pregnancy progressed. CONCLUSION: SCH during pregnancy is associated with a high incidence of various pregnancy complications, and LT4 therapy that controls serum TSH levels at normal levels throughout pregnancy can reduce these risks.