What does the Down syndrome screening test check for? What are the main tests performed?

Patient's question:

No

Doctor's answer:

Analysis of the condition: Hello, the Down syndrome screening involves drawing blood from the pregnant woman, separating the serum, and testing the serum to calculate the risk factor for giving birth to a fetus with congenital defects. The best time for Down syndrome screening is between the 9th and 14th weeks.
Advice: Hello, the Down syndrome screening is used to check if the baby may have the possibility of having Down syndrome after birth (whether the child is mentally retarded).