What is prenatal diagnosis? Prenatal diagnosis, also known as prenatal diagnosis or intrauterine diagnosis, refers to the application of various methods to check whether the fetus has serious genetic diseases, mental retardation and congenital anomalies before the birth of the fetus, so as to implement appropriate measures such as early treatment, termination of pregnancy, early delivery, etc., as well as postnatal treatment. Liu Ning, Genetic and Prenatal Diagnostic Center, First Affiliated Hospital of Zhengzhou University Which pregnant women need prenatal diagnosis? 1. High-age pregnant women (age 35 or older) 2. Pregnant women with high risk of Down’s syndrome screening during pregnancy 3. Ultrasound suggests that the fetus has structural abnormalities 4. Pregnant women where one of the spouses is a carrier of chromosomal translocation or other chromosomal anomalies 5. Pregnant women where there are known or suspected genetic diseases in the family, where one of the spouses is a patient with a single-gene disease or where the couple has given birth to children with single-gene diseases 6. Fetuses with high risk of chromosomal abnormalities, such as those who have had children with chromosomal abnormalities 6. Pregnant women with high risk of chromosomal abnormalities Chromosomal abnormalities, such as having a child with chromosomal abnormalities, neural tube malformations or developmental abnormalities, and other adverse maternal history 7. Pregnant women who are suspected of having a high risk of intrauterine infection 8. Pregnant women whose obstetrician believes that the fetus is at risk of an abnormality according to the clinical assessment Types of Interventional Prenatal Diagnostic Puncture and Timing Currently, there are three types of interventional prenatal diagnostic puncture carried out by the hospital: chorionic villus, amniotic fluid, and umbilical cord blood puncture. The physician will consider the patient’s pregnancy and the timing of the procedure. The physician will choose different methods of puncture according to the different gestation periods and indications of the pregnant women. Chorionic villus aspiration: usually performed at 10-14 weeks of pregnancy Amniocentesis: usually performed at 16-24 weeks of pregnancy Umbilical cord blood sampling: usually performed after the 24th week of pregnancy How does an Interventional Prenatal Diagnostic Surgery work? Interventional prenatal diagnostic procedures are usually performed under the guidance of ultrasound, the role of ultrasound is to choose to avoid the appropriate part of the fetus for puncture, the examination requires a thin needle to obtain fetal tissue samples, in fact, the process is very similar to the injection. Will the prenatal diagnostic procedure be painful? A small number of pregnant women may experience slight discomfort during the procedure. Most pregnant women return to their normal activities soon after the procedure. What is the risk of fetal miscarriage after an Interventional Prenatal Diagnostic Puncture? Interventional Prenatal Diagnostic Puncture has the potential to cause fetal miscarriage, with the chance ranging from 0.5 to 1% in chorionic villus sampling, approximately 0.2 to 0.5% in amniocentesis, and about 1% in umbilical vein puncture. It may also cause bleeding from the umbilical cord and placenta, fetal bradycardia, and intrauterine infections, but the incidence is low.