I hope to be of help to the mothers and fathers-to-be by answering more questions in the future. I hope to help the mothers and fathers-to-be. Is there radiation Oh First of all, science, ultrasound is a discipline of acoustics, is different from the optics such as x-ray film, it is formed by sound transmission to certain substances after the formation of echoes, the instrument then receives different echoes through computer processing to form the image. Ultrasonography, as a non-invasive prenatal diagnostic technique, is widely used in clinical practice for its simplicity, rapid diagnosis and repeatability. At present, it has tended to be popularized, early and repeated. When a pregnant woman goes to the hospital for a maternity checkup, an ultrasound examination is essential. Ultrasonography can determine the gestational week, diagnose fetal structural malformations, and monitor fetal intrauterine development. With the widespread use of ultrasound, there is also concern about the safety of ultrasound examinations. The mechanisms of action of ultrasound in human tissues are divided into two categories: thermal and mechanical effects. Thermal and mechanical indices are incorporated into ultrasound safety standards, and there are corresponding safety indicators for the acoustic output of ultrasound examinations. The corresponding parameters set by the color Doppler ultrasound diagnostic instruments in use nowadays have not been identified to cause harmful biological effects reported. The number of ultrasound examinations needed during pregnancy (excluding special cases: multiple pregnancy, placenta praevia, intrauterine distress, etc.), combined with the current situation of ultrasound examination in our department, the ultrasound examinations needed throughout pregnancy are as follows: 1. 7 weeks of pregnancy (to determine whether the pregnancy is intrauterine and whether there is a fetal heart) 2. 11-13 6 weeks of pregnancy (to measure NT value) 3. 14-20 weeks of pregnancy (to determine the gestational week and level I examination) 4. 22-24 weeks (systemic ultrasound, fetal heart ultrasound, screening for fetal structural malformations. 5.30-32 weeks of gestation (to monitor fetal growth and development and screen for late onset fetal malformations) 6.37-38 weeks of gestation (to assess the size of the fetus and the condition of the amniotic fluid and placenta) 7, before delivery according to the doctor needs to carry out the appropriate ultrasound examination. The ultrasound can detect all the fetal malformations, but it cannot detect all the malformations. Obstetric ultrasound examination is affected by the thickness of the abdominal wall fat, abdominal wall scar, fetal gestational week, fetal position, amniotic fluid, placenta and many other factors (think about the principle of ultrasound to understand, if I speak with the same frequency, you can hear clearly in this room, but you can hear clearly in the next room!) The ultrasound can’t show all the structures of the fetus’ body, such as the soft tissues of the skin, fingers, toes, whether it has double eyelids, and whether it has birthmarks, so not all malformations can be screened. The original name of color ultrasound is “color Doppler ultrasound”, which is based on two-dimensional images using the Doppler principle to show the blood flow of internal organs or cardiovascular, so we usually enable two-dimensional image examination first, and then enable color Doppler mode when necessary. Auxiliary diagnosis, and the regular hospital outpatient clinics used are color ultrasound examiner.