Four-dimensional color Doppler usually looks at about 234 weeks. Now basically every hospital has to make an appointment in advance. If you want to do it in that hospital, you have to make an appointment for more than ten weeks. If you wait for more than 20 weeks, there may be no places at that time, and it will not work. You just need to hang up the number of that hospital, and then tell the teacher that you have encountered a four-dimensional color Doppler ultrasound, and they will open it for you, and then determine the time. If the time is up.