Do I need to make an appointment in advance?

In general, four-dimensional color Doppler ultrasound needs to make an appointment in advance, but whether an appointment is required, you also need to consult the hospital where the examination is located. Between 22 weeks of pregnancy and 28 weeks of pregnancy, it is time to do four-dimensional color Doppler ultrasound, but the best time to do four-dimensional color Doppler ultrasound is about 24 weeks of pregnancy, that is, about 6 months pregnant. about 24 weeks of pregnancy, at this time the fetus size is moderate, and the fetus has basically developed into shape, four-dimensional color Doppler examination can clearly see whether the fetus has facial deformity, whether there are short limbs and whether there are congenital heart disease and other abnormalities.