Abstract: Normal maternal thyroid function plays an important role in fetal growth and development.However，hyperthyroidism during pregnancy，an endocrine disorder，is frequently seen.Moreover，its treatment during lactation is associated with the recovery of maternal and neonatal thyroid function.We introduced the mechanisms of action and adverse reactions of antithyroid drugs（ATDs），such as methimazole（MMI） and propylthiouracil（PTU），briefly described the effects of treatment with different doses of ATDs at different time points during pregnancy and lactation on maternal，fetal and neonatal thyroid functions，and based on this，we recommended PTU for treatment during first trimester，MMI for treatment during second and third trimester.Furthermore，we encouraged mothers to receive the treatment with ATDs during lactation，and low- to medium-dose MMI was suggested for first-line treatment，and PTU for second-line treatment.In addition，we suggested that appropriate treatment with ATDs during pregnancy and lactation could not significantly affect fetal and neonatal physical and intelligence development（including thyroid function）．

Key words: Hyperthyroidism, Antithyroid agents, Methimazole, Propylthiouracil, Pregnancy, Lactation