Low thyroid stimulating hormone during pregnancy has little or no effect on the fetus if thyroid hormone levels are normal; persistently high thyroid hormone levels may affect the fetus. If only low thyroid stimulating hormone is present during pregnancy and thyroid hormones are normal, there is usually no significant effect on the fetus and continuous observation and follow-up is possible. If low thyroid stimulating hormone is accompanied by persistently elevated thyroid hormone levels, it may be a sign of hyperthyroidism or hyperthyroidism in pregnancy. Hyperthyroidism is mostly abnormal when it is often accompanied by elevated thyroid-related antibodies such as globulin antibodies and thyroid-stimulating hormone receptor antibodies. It may lead to fetal growth retardation, intrauterine hypoxia, asphyxia, and even death. Aggressive pharmacologic intervention is therefore required. Hyperthyroidism syndrome in pregnancy often has no antibody abnormality, and as the pregnancy progresses to the mid-pregnancy this condition can be relieved on its own, it is a normal state, basically has no effect on the fetus, pay attention to rest and regular recheck can be. It is recommended to consult a doctor for standardized diagnosis and treatment if necessary.