Hypothyroidism during pregnancy does not usually lead to autism in babies, although hypothyroidism during pregnancy may affect the intellectual development of the child. The thyroid gland is an important hormone that promotes protein synthesis, which is important for the neurological development of the fetus. At 10-12 weeks of pregnancy, the fetal thyroid gland is not able to gather iodine, and before 20 weeks of pregnancy, the fetus is not able to synthesize or secrete thyroid hormones by itself. Therefore, it is strictly dependent on maternal T4 penetration into the placenta to maintain thyroid function. If the mother lacks thyroid hormone during pregnancy, then the fetus has no way to synthesize it on its own, which can easily lead to the protein synthesis of the fetus being affected, which in turn may affect the intelligence of the fetus. Therefore, if abnormal thyroid function is detected during pregnancy, then it is recommended to consult a doctor in time and choose the appropriate way of treatment.