Patient's question:
A relative of a friend is pregnant and is planning to go to the hospital for a prenatal screening test. They said it involves blood tests, so they want to understand if the screening requires multiple blood draws.Doctor's answer:
The best time for screening is between the 9th and 14th days of pregnancy. Early pregnancy screening is preferable, as missing it in the mid-pregnancy period increases the risk of a positive result, which poses greater harm to the mother. Chorionic villus sampling (early), amniocentesis, and fetal chromosome examination (mid-pregnancy) can provide a definitive diagnosis for high-risk cases. Pregnant women only need to fast and provide 2ml of venous blood, which can be drawn 12 hours after the last meal. Results will be available 2-3 weeks after blood collection. For Down syndrome screening, blood tests are required twice—once in early pregnancy and once in the mid-pregnancy period. Don’t be too nervous.