With the introduction of the national “two-child” system, more and more parents are preparing to have a second baby, but we often see pregnant women clinically for abnormal thyroid function, which is related to the fact that the popularity of thyroid knowledge is still low and thyroid screening has not yet been included in the routine pregnancy tests in China. 1. What are the common abnormalities of thyroid function in pregnancy? The common abnormalities of thyroid function in pregnancy include: pregnancy combined with subclinical hyperthyroidism, pregnancy combined with hyperthyroidism, pregnancy combined with subclinical hypothyroidism, pregnancy combined with hypothyroidism, pregnancy combined with Hashimoto’s thyroiditis. 2. What are the risks of pregnancy combined with abnormal thyroid function? Abnormal thyroid function in pregnancy can cause miscarriage, premature birth, stillbirth, intrauterine growth retardation, congenital malformations and abnormal thyroid function in infants. Subclinical hyperthyroidism in pregnancy is sometimes caused by a gradual increase in hCG levels during pregnancy, reaching a peak in the third trimester. hCG has the same alpha subunit, similar beta subunit and receptor subunit as TSH, so it has a mild stimulating effect on TSH receptors in thyroid cells, leading to suppression of the pituitary-thyroid axis and lower than normal serum TSH. Although no medication is needed for the time being, regular review of thyroid function is required. Pregnancy combined with hyperthyroidism affects both the pregnant woman and the fetus. In order to control it, the pregnant woman is prone to miscarriage, premature birth, congestive heart failure, hyperthyroidism crisis, infection, etc. For the fetus, it may affect fetal development and cause neonatal hyperthyroidism and stillbirth. Therefore, early detection and treatment of hyperthyroidism during pregnancy is essential. Pregnancy combined with subclinical hypothyroidism may cause infertility, spontaneous miscarriage, premature birth, fetal growth restriction, fetal distress, placental abruption, gestational hypertension, pre-eclampsia, glucose metabolism abnormalities in pregnancy, anemia and so on. The clinical signs of hypothyroidism may or may not be present in pregnant women. Pregnancy combined with hypothyroidism not only has the above mentioned risks of subclinical hypothyroidism, but also affects the intelligence of the fetus. In China, the prevalence of hypothyroidism in pregnancy is high, with nearly 1 in 10 pregnant women suffering from hypothyroidism in pregnancy, with clinical manifestations such as lack of energy, lethargy, weight gain, fear of cold, constipation and memory loss. The clinical manifestations include energy, lethargy, weight gain, coldness, constipation and memory loss. Hashimoto’s thyroiditis in pregnancy may initially appear as hyperthyroidism, but with the destruction of the thyroid gland, it will eventually appear as hypothyroidism, so it will also have an impact on the intelligence of the fetus, and the pregnant women are more likely to miscarry and deliver prematurely than normal. 3.Why does pregnancy combined with abnormal thyroid function affect the fetus? The reason is that thyroid hormones are needed for the development of the fetal brain. During the first 12 weeks of pregnancy, the fetus is in the first rapid stage of brain development, but at this time, the fetus’ own thyroid function has not yet been established, so the thyroid hormones needed for fetal brain development are completely dependent on the mother’s supply. 4. At what gestational week should thyroid screening be performed during pregnancy? Thyroid examination should be performed before 12 weeks of pregnancy, preferably in advance during pregnancy preparation. 5.How to avoid the danger of abnormal thyroid function in pregnancy to the fetus? Early screening: Women of childbearing age should go to the endocrinology department or related departments of regular hospitals to have their thyroid function tested before pregnancy. Usually, the doctor will take a certain amount of venous blood from the subject for testing, and the test results will be available on the same day or the next day. Early treatment: The treatment of pregnancy combined with abnormal thyroid function is simple and effective. That is, medication can be taken throughout the pregnancy and breastfeeding period. 6.How to treat after the diagnosis is confirmed? If abnormal nail function is found before pregnancy, medication can be used to adjust nail function to a level that allows conception before pregnancy. If you find abnormal A function during pregnancy, you should go to a regular hospital for treatment as soon as possible, and the dosage of medication should be adjusted continuously throughout pregnancy. It is important to know that the earlier the TSH standard is reached, the less impact it will have on fetal brain development.