Normal fertility women need to go to the obstetrics department of the hospital at about 12 weeks of pregnancy to build a card to register for a comprehensive examination, and wait until the 24th week of pregnancy need to do a four-dimensional ultrasound examination, the main purpose is to rule out the fetal parenchymal organs with or without malformations. Obstetrics and gynecology four-dimensional ultrasound cost are about 400 yuan, not only to specialize in detecting the fetal brain, limbs and abdominal conditions, at the same time to specialize in four-dimensional ultrasound examination of the fetal heart, in order to rule out whether there is congenital heart disease. Because 4D ultrasound examinations usually take longer, pregnant women who need a 4D ultrasound need to make an appointment in advance. Usually in about 16 weeks of pregnancy should be to the ultrasound room to make an appointment to register, so as not to miss the best time for the examination, because it is for the ultrasound examination can not be more than 28 weeks.