Thalassemia is a recessive blood disorder mainly found near the Mediterranean Sea, south of the Yangtze River in China and Southeast Asia, and is a single gene genetic disease. Thalassemia can be subdivided into type A (alpha) and type B (beta). If a couple is a carrier of the same type, there is a 1/4 chance that their fetus will be completely normal, 1/2 chance that it will become a carrier, and 1/4 chance that it will become a heavy patient in each pregnancy. If the fetus is thalassemia major, it will develop fetal edema after the middle of pregnancy, including ascites and placenta enlargement, which can be detected by ultrasound, and most of the fetuses will die soon after birth, and a few will die in utero. If the fetus is thalassemia major, the ultrasound does not show any abnormalities. However, after a few months of life, the newborn becomes anemic and requires regular blood transfusions for life or a bone marrow transplant to save the baby’s life. Therefore, it is important for pregnant women to be screened for thalassemia carriers. If a pregnant woman is found to be a thalassemia carrier during prenatal screening, her spouse should also be screened and if they are found to be carriers of both thalassemia genes, prenatal genetic diagnosis should be performed for the fetus in her womb. If the genetic diagnosis reveals that the fetus has intermediate or severe thalassemia, the pregnant woman should be advised to terminate the pregnancy; if the fetus is normal or mild, the pregnancy can continue.