Hypothyroidism can cause abnormal menstruation, leading to infertility, and pregnancy can impair the neurointellectual development of the offspring and increase the risk of adverse pregnancy outcomes. Hypothyroidism can lead to menstrual disorders and excessive menstruation in women, leading to infertility. Clinical hypothyroidism in pregnancy is diagnosed when TSH is > upper limit of the reference range for gestational age and free T4 is < lower limit of the reference range for gestational age. Clinical hypothyroidism in pregnancy without standardized treatment impairs the neurointellectual development of the offspring and increases the risk of adverse pregnancy outcomes, including preterm birth, low birth weight babies, stillbirths, and miscarriages, and increases the risk of hypertensive disorders in pregnancy. Clinical hypothyroidism in pregnancy can be treated with optional oral treatment with levothyroxine sodium tablets to control TSH to 1/2 of the pregnancy-specific reference range, or less than 2.5 mIU/L. Hypothyroidism is a common disease in endocrinology and obstetrics. Routine screening is recommended for women who are preparing for pregnancy, and thyroid function should be screened as soon as possible after pregnancy, so that once abnormalities are detected, they can be treated in time to minimize their adverse effects.