People say obstetrics and gynecology, but in fact it is divided into two disciplines: gynecology and obstetrics. Ultrasound plays a very important role in gynecology and obstetrics, vaginal ultrasound is recommended in gynecology if there are no special contraindications, and abdominal ultrasound is recommended in obstetrics. Especially nowadays, 4D ultrasound and 3D ultrasound are used for fetal screening in obstetrics, which play a very important role in early detection of fetal malformation and eugenics!