What does prenatal screening include?

What everyone should understand is that prenatal diagnosis is a predictive method, not a diagnosis, but if the screening result is high-risk, effective measures should be taken immediately. There are many important prenatal diagnosis items in prenatal examinations, and pregnant women must remember to have regular prenatal examinations to complete these screening items. Let’s discuss what is included in prenatal diagnosis.

The first is NT screening, which requires pregnant women to go to the hospital for color ultrasound between 11-14 weeks to test the NT value, which refers to the thickness of the transparent layer on the fetal neck. If the NT value is greater than 2.5mm, the fetus will be at risk of Down syndrome or congenital heart disease. Mid- to late-term Down syndrome screening is done between 15 and 21 weeks of gestation. Venous blood is drawn from the pregnant woman, and the risk of the fetus having Down syndrome is calculated by testing the concentrations of HCG, free estriol and alpha-fetoprotein in the blood, combined with the pregnant woman's age, weight, and weeks of pregnancy. Diabetes screening is needed after 24 weeks of pregnancy. Venous blood should be drawn from the pregnant woman to test postprandial blood sugar or a glucose tolerance test should be performed. If the pregnant woman has high blood sugar, she should control her diet or use medication as instructed by the doctor to avoid causing large fetuses or affecting the physical and mental health of the mother and child.

What exactly does prenatal diagnosis screen for? Prenatal diagnosis mainly selects three types of congenital defects with relatively high prevalence rates for screening, including Down syndrome, trisomy 18 and open neural tube defects.

The above three congenital defects have a relatively high incidence rate. Although congenital defects such as neural tube defects and congenital idiocy are genetic diseases, they are also greatly affected by environmental factors. Therefore, their occurrence has a certain degree of randomness. It is difficult to eliminate the possibility of occurrence based on family history and pregnancy history. Therefore, all pregnant women who meet the conditions should participate in prenatal diagnosis.