A 3-D ultrasound is usually performed to see the baby’s ears. Three-dimensional ultrasonography is one of the commonly used examinations in obstetrics and gynecology and is usually done around 20 to 24 weeks of pregnancy. It is mainly used to check the development of the fetus’s head, face and five senses, limbs and trunk, organs, etc., and to rule out malformations; it can also be used to assess the overall growth and development of the fetus by measuring the biparietal diameter, head circumference, abdominal circumference, and so on. The 3D ultrasound examination can usually observe whether there is any abnormality of the placenta and umbilical cord, such as whether there is placenta previa, placenta previa, umbilical cord around the neck, etc.; it can also determine whether the amniotic fluid is too little, too much, etc., and can take timely and appropriate treatment measures so as to avoid any adverse effects on the pregnant woman and the baby. If the result of 3D ultrasound examination is abnormal, you should consult a doctor in time, clarify the cause of the disease with the help of the doctor, and carry out targeted treatment.