With the continuous development of medical technology, ultrasound has become a routine examination essential for clinicians’ diagnosis. Each pregnant mother usually needs to have 5-6 ultrasound examinations during her maternity checkup to understand the growth and development of the fetus in the pregnant woman’s womb. However, some pregnant women are particularly concerned about the adverse effects of more ultrasound on the fetus. What exactly are 3D and 4D? According to the summary of the World Federation of Ultrasound in Medical Biology statement, the sound power of the B-mode ultrasound imaging equipment currently in use is unlikely to have a harmful temperature-raising effect. Experimental animal studies clearly show that less than 38.5°C can be used widely, including for obstetric applications. This means that the ultrasound scan used to obtain images of your baby generates very little heat, and because of the low intensity of the ultrasound used and the wide range of the scan, it will not cause excessive heat to your baby. Plus your baby is moving again and the surrounding amniotic fluid helps to disperse the heat. So, pregnant mothers do not have to be overly concerned. What is a color ultrasound? Color ultrasound is not in color like a television set. The difference between the so-called color ultrasound and black and white ultrasound is that besides the fact that color ultrasound has better clarity and contrast than black and white ultrasound, color ultrasound can also use color signals to mark indicators such as blood flow and see information about the heart, blood vessels and the direction of blood flow, such as cord winding, vessel anterior, umbilical artery, middle cerebral artery, umbilical cord entrance, aneurysm and other information related to blood flow, and it can also be used for It can also be used to identify some diseases such as hydrocele and pelvic vessels, etc. What is 3D and 4D ultrasound? Nowadays, what we usually call: 4D: generally refers to the screening of fetal malformations in mid pregnancy; 3D: refers to the screening of fetal malformations in late pregnancy. Because 4D-3D is a more advanced ultrasound technology, not only can this technology be used to image the baby and allow the mother to see what her baby looks like, but it can also be used to diagnose and differentially diagnose some fetal abnormal structures, so it is extra important to do fetal system examinations among all ultrasound examinations during pregnancy. They are one of the essential and important tests for prenatal screening of fetal anomalies, with the aim of ruling out serious fetal malformations through ultrasound. It is generally recommended to have two fetal systemic screening examinations, or what we often call 4D-3D, throughout pregnancy, respectively, in mid-trimester and late-trimester, so that you can remember the importance of these two examinations. How to make an appointment? The fetus in the middle of pregnancy is the most important examination in the whole pregnancy because the organs are basically developed and there is a certain space for movement in the mother’s womb, which is conducive to the doctor’s observation of the baby and timely detection of problems during the examination, so the mid-pregnancy system screening is the most important one. However, because the examination is more extensive and takes longer, an appointment is required. The 4D ultrasound examination usually takes place around 20-26 weeks of pregnancy, so it is recommended that all pregnant mothers make an appointment for 4D during the 15-18 weeks of pregnancy. The 3D ultrasound is usually performed at 28-36 weeks of pregnancy and is a supplement to the mid-term fetal system examination. It is recommended that pregnant mothers make an appointment at 22-24 weeks of pregnancy, preferably after the 4D is done. Before coming to do 3D and 4D pregnant women do not need special preparation and can eat. If the doctor indicates that some pregnant women need to see the position of the placenta or the inner cervical opening, they need to drink water and hold urine, otherwise the cervix will not be displayed. Some fetuses are not in a good position for the doctor to observe, so the pregnant women need to get up and move around and eat something sweet to make the fetus turn to a better position. Therefore, pregnant women can prepare some snacks or chocolates before they come for the screening. The 3D and 4D ultrasound examinations have high requirements on the qualification and technology of the operating physician, not only to leave an intrauterine “portrait” of the unborn baby, but more importantly, to observe the fetus in multiple directions and angles, monitor the fetal growth and development in the uterus, provide accurate scientific basis for fetal malformation screening, and prevent birth defects. It provides an accurate scientific basis for fetal anomaly screening and prevents birth defects. Fetal system ultrasound can rule out most fetal anomalies, especially anencephaly, open spina bifida, severe meningocele, severe cleft abdominal anomaly, single-chambered heart, lethal osteogenesis imperfecta and other serious anomalies.