The placenta of a full-term pregnancy weighs between about 450-650g. However, if the pregnant mother suffers from some diseases, such as hypertensive syndrome during pregnancy, diabetes, syphilis or certain viral infections, as well as multiple births and fetal baby with thalassemia major, a huge placenta may occur. This means that the weight of the placenta exceeds the normal range, and the fetal baby may also be affected to varying degrees at this time. We all know that the exchange of nutrients and wastes, as well as gases, between the baby and the mother is done through the placenta. In addition to this function, the placenta also provides a protective barrier for the baby, but this protective effect is very limited, for example, most viruses and drugs may pass through the placenta and affect the baby’s growth and development, so when placental abnormalities occur, we have to further evaluate whether the baby has abnormalities.