The thyroid gland is an important endocrine organ and its secretion of thyroxine is an important hormone that regulates the body’s metabolism. Abnormal thyroid function is not uncommon in people of reproductive age, especially in women, where the incidence is about 4-5 times higher than in men. Thyroxine secreted by the thyroid gland is closely related to the secretion and effect of female sex hormones, which directly affects the reproductive function of women. The clinical presence of hyper- or hypothyroidism or autoimmune thyroiditis can interfere with human reproductive physiology, cause menstrual disorders, reduce the chances of conception, and adversely affect the outcome of pregnancy, which deserves attention. Thyroid hormone secreted by the thyroid gland can have the following effects on ovarian function: 1. directly participate in and influence the metabolism of ovarian estrogen, which is an important factor indispensable in the synthesis, decomposition and transformation of human steroid hormones; 2. regulate ovarian function through the secretion of pituitary gonadotropin, i.e. follicle stimulating hormone and luteinizing hormone; a small amount of thyroid hormone promotes the secretion of luteinizing hormone; a moderate amount of thyroid hormone A small amount of thyroid hormone promotes the secretion of luteinizing hormone and a moderate amount of thyroid hormone maintains the balance between pituitary and gonadal functions, while a large amount of thyroid hormone inhibits the secretion of gonadotropins; 3. Thyroid hormone can have a direct inhibitory effect on the ovaries, reducing the responsiveness of the ovaries to pituitary gonadotropins; 4. Patients with hypothyroidism are often associated with abnormalities in reproductive function such as luteal insufficiency, non-ovulation, and persistent proliferative state of the endometrium; patients with ovulation have decreased conception rates and higher miscarriage rates. Pregnant women with hypothyroidism have a significantly increased risk of miscarriage, preterm delivery, gestational hypertension, and stillbirth for both mother and child. It is recommended that women have thyroid function tests before planning a pregnancy.