Low thyroid stimulating hormone in pregnant women may have hyperthyroidism, and pregnant women will have emaciation, fear of heat, excessive sweating, increased frequency of stools and other manifestations, and in serious cases, it may cause gestational hypertension, congestive heart failure, low birth weight of the fetus, preterm delivery or even miscarriage and other adverse consequences. If a pregnant woman has low thyroid stimulating hormone and increased T3 and T4, it suggests hyperthyroidism. The main role of thyroid hormone is to promote the body’s metabolism, when the metabolism of pregnant women is hyperfunctioning, it can not provide sufficient nutrition for the fetus, which further affects the growth and development of the fetus, resulting in its low birth weight. Pregnant women with hyperthyroidism will lose weight, be afraid of heat, sweating, easy to get excited, and increase the number of bowel movements and other manifestations. Hyperthyroidism in pregnant women is also associated with a high risk of gestational hypertension and congestive heart failure. If the hyperthyroidism during pregnancy is not effectively controlled, it can also cause preeclampsia, which can lead to preterm labor, miscarriage and other negative consequences. If a pregnant woman’s thyroid hormone is low, she should seek medical advice and treatment under the guidance of a doctor, and should not take medication without authorization in order to avoid delaying her condition. Pay attention to rest on weekdays, quit smoking and drinking, and eat a reasonable diet.