How long does it take to do four-dimensional color Doppler ultrasound?

Four-dimensional color Doppler ultrasound refers to fetal large row abnormal color examination, generally in 20 to 24 weeks of pregnancy for a row abnormal examination. Therefore, in this gestational week to do large row abnormal color Doppler ultrasound, because this time amniotic fluid status and fetal size is moderate, fetal movement space is large, the clearest vision, is the best time to screen for abnormalities. Although it is called four-dimensional, it is real-time dynamic three-dimensional color ultrasound. Four-dimensional color Doppler ultrasound is mainly used to display some abnormalities of fetal body surface, such as cleft lip and palate, special structural abnormalities of face, structural abnormalities of limbs or trunk surface, etc., as well as six major abnormalities including anencephaly, severe encephalocele, severe open spina bifida, severe visceral valgus, single chamber heart, fatal bone dysplasia, etc., as well as morphological observation of fetal main organs.