The effects of high thyroid hormone in pregnant women on the fetus are commonly as follows: 1, leading to difficult delivery: Because of high thyroid gland, the uterus may contract weakly during labor, which may easily lead to difficult delivery and affect the birth of the fetus. 2, causing hypothyroidism in pregnant women: Hypothyroidism in pregnant women may have certain effects on the fetus, which may easily lead to miscarriage, premature delivery or placental abruption, affecting the growth and development of the fetus. 3. Causes hyperthyroidism in newborns: If the mother has high thyroid hormones, the newborn may have hyperthyroidism, such as redness, irritability, frequent sweating, and very light weight and very large food intake. So once a woman is checked for high thyroid hormones, she should follow her doctor’s advice and have regular checkups to avoid bad effects on the fetal baby.