Down’s syndrome screening can be done after 13 weeks of pregnancy to rule out the possibility of congenital dysmorphism. In addition, 2D ultrasound can be done at around 16 weeks of pregnancy for preliminary screening. Between 23 and 28 weeks of pregnancy, 4D ultrasound can be done. Through 4D ultrasound stereoscopic imaging, the development of fetal internal organs, whether there are deformities in fetal soft tissues, and whether the fetal limbs are developing normally can be checked more clearly, so it is recommended that these stages of the screening must be done. You need to make an appointment for 4D ultrasound, and it is recommended that you can pay for the bill around 21 weeks, and then make an appointment. It is recommended to give regular maternity checkups during pregnancy in addition to the screening tests.