The thyroid gland is the largest endocrine organ in the body, thyroid disorders are common endocrine diseases, and women of childbearing age are at high risk for thyroid disorders. Women with abnormal thyroid function are prone to infertility, menstrual disorders and pregnancy complications, and may have long-term effects on the health of their offspring. Abnormal thyroid function includes hyperthyroidism (referred to as hyperthyroidism) and hypothyroidism (referred to as hypothyroidism). If thyroid function is disordered, it can affect a woman’s reproductive function in a number of ways. 1, hypothyroidism and infertility There are reports in the literature that the prevalence of hypothyroidism in women of childbearing age is about 2-4%, and there are also a considerable number of patients with subclinical hypothyroidism, which has no relevant clinical manifestations and needs to be confirmed by TSH screening, whether it is clinical hypothyroidism or subclinical hypothyroidism, it will have a greater impact on women’s reproductive function. Hypothyroidism leads to scanty menstruation and even amenorrhea in women. The onset of hypothyroidism in adulthood is often associated with anovulation, menstrual disorders, sexual dysfunction and infertility. Clinical hypothyroidism not only affects fertility, but it is also three times more likely than normal to cause hypertension, placental abruption, spontaneous abortion, preterm birth and low birth weight babies during pregnancy. In mothers with clinical hypothyroidism, especially before 20 weeks of gestation (before the fetal thyroid function is fully established), because the fetal brain needs thyroxine mainly from the mother, if the mother is hypothyroid, then the fetal thyroxine intake will be insufficient, which directly affects the fetal mental development, resulting in a child born with mental retardation, called cretinism (cretinism). At the same time, research has found that if a mother with hypothyroidism is not treated during pregnancy, the child’s IQ at the age of 7-9 years can be reduced by 7 points compared to normal children. 2. Hyperthyroidism and infertility Hyperthyroidism is also associated with irregular menstruation and infertility in women. In addition to the changes in sex hormone levels in patients with hyperthyroidism, the causes of infertility due to hyperthyroidism may also be related to mental factors such as stress, panic, anxiety and immune dysfunction. It is generally accepted that severe hyperthyroidism can lead to infertility. It is uncertain whether mild to moderate hyperthyroidism can lead to infertility, but patients with hyperthyroidism, including those with subclinical hyperthyroidism, have a significantly increased rate of miscarriage and other adverse pregnancy outcomes after conception. In moderate to severe hyperthyroidism, feedback inhibition of TRH, TSH, and GnRH secretion leads to anovulatory menstruation or amenorrhea, causing infertility. In addition, patients with hyperthyroidism are often mentally stressed and have high mood swings. Patients often have hyperplasia of the adrenal cortex, 38% have combined diabetes, and all patients have varying degrees of vitamin B and A deficiency. These factors may lead to a decrease in fertility. In women with hyperthyroidism combined with pregnancy, if the treatment of hyperthyroidism is inadequate, even if pregnancy occurs, miscarriage, preterm delivery, fetal growth retardation (IUGR), intrauterine death, etc. are likely to occur. Therefore, women of childbearing age should have their thyroid function checked regularly and maintain a positive and optimistic attitude towards life. If you find abnormalities, you should go to a regular hospital for blood tests and thyroid ultrasound to confirm the diagnosis and standardize treatment as soon as possible. If you are suffering from hypothyroidism, you should make your thyroid function meet the standard through treatment before conceiving and raising the next generation, and women with hypothyroidism during pregnancy should be treated with drug intervention as soon as possible to ensure the health of mother and child.