Thyroid hormone is a hormone with important physiological functions in the body, so normal and good functioning of the thyroid gland has a significant positive effect on both the fetus and the pregnant woman. Insufficient production of thyroid hormones by the thyroid gland is known as hypothyroidism. This abnormality can lead to a risk of miscarriage and fetal death in late pregnancy. The thyroid gland does not produce enough thyroid hormones to meet the needs of the pregnant woman’s body, and she can also suffer from emotional problems such as mental distress and memory loss, which can cause serious problems for the health of the pregnancy. Hypothyroidism can also have a serious impact on the fetus. Thyroid hormones boost fetal metabolism and promote neurological development. Once a woman develops this problem during pregnancy, it may lead to abnormal development of the fetus’ organs in the womb, significant delays in intrauterine development, and abnormal intelligence due to abnormal neurodevelopment. Excessive secretion of thyroid hormones during pregnancy is known as hyperthyroidism. This disease can cause heart problems such as panic attacks and shortness of breath in pregnant women, and can also cause problems such as emotional impatience and easy fatigue. If not effectively controlled, it can also lead to more serious heart failure, thyroid crisis and other problems, which may lead to death. This condition can also lead to problems such as fetal death and premature birth. Normal thyroid function is important for women during pregnancy, so pregnant women should do thyroid-related examinations and take timely treatment if problems are found to prevent abnormalities in the pregnancy and fetus.