Question
What does a 1 in 15 high risk value for Down syndrome screening mean? (Age: 26 years, Height: 160cm, Weight: 61kg, Gestational Age: 16 weeks 6 days (calculated from last menstrual period), Last Menstrual Period: March 15, 2013, Actual Date: March 25, 2013. Inquiring about the impact of the error in the last menstrual period value on the screening result, and why my risk value is 1 in 15, while others are typically 1 in a few hundred.)
Answer
Down syndrome, also known as trisomy 21, refers to an extra chromosome on the 21st pair. Down syndrome screening involves testing the levels of alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) in the pregnant woman’s serum, combined with her age, weight, and gestational age to calculate the risk value. The critical value is 1 in 275, with values higher than this considered high risk and those lower considered low risk. The general population (under the age of 37) has a chance of 1 in 750 of developing Down syndrome. If the screening result is high risk, it is recommended to undergo amniocentesis. Even if the result is high risk, it does not necessarily mean the child will have Down syndrome. However, for safety reasons, further testing is recommended. Children with Down syndrome often suffer from severe intellectual disabilities and complex cardiovascular diseases, requiring long-term care and placing a significant burden on families.