Grand Rounds can be either 3-D or 4-D. A grand mal refers to an ultrasound that is done between 22-26 weeks of pregnancy to screen the fetus for malformations. Generally, it can be done by fetal 3D ultrasound, and some hospitals can do 4D ultrasound. Compared with 3D ultrasound, 4D ultrasound has an additional dimension of time. After the 4D ultrasound, there will be a video of the examination process as a souvenir. In terms of the accuracy of the examination, there is no significant difference between 3D and 4D ultrasound, and the accuracy depends on the skills of the examiner and the examination equipment. If there are no special circumstances, it is fine for pregnant women to have 3D ultrasound. In addition, in addition to the major abnormal ultrasound at 24 weeks, a minor abnormal ultrasound is also needed between 32 and 34 weeks, which is also possible in either 3D or 4D. Another ultrasound is needed at 38 weeks of pregnancy, when a 3D ultrasound can be done, mainly to see the size of the fetus and to assess whether it can be delivered vaginally. During the grand mal, the doctor will carefully screen the fetus from the head to the feet. If the grand mal reveals any abnormality in the fetus, prenatal diagnosis is recommended, and a fetal heart ultrasound is also done to rule out congenital heart disease. You can also look at the depth of amniotic fluid, amniotic fluid index, placental position, placental maturity, and whether the umbilical cord is wrapped around the neck. If the umbilical cord is found to be wrapped around the neck, pregnant women should pay close attention to monitor fetal movement, and if they feel a significant decrease in fetal movement or a decrease in the magnitude of fetal movement, they should seek medical consultation in time. It is recommended that pregnant women choose a prenatal diagnosis center or a large tertiary hospital to have an ultrasound because it is a more important examination during pregnancy. If the pregnant woman is obese and has thick abdominal wall fat, it may take a little longer to do the major abnormality.