Down Syndrome Screening Flashcards
1
Q
When does the neural tube close?
A
6 weeks
2
Q
What is the population prevalence of downs syndrome?
A
1/500
3
Q
What is the maternal age cut off for screening?
A
37
4
Q
What makes up the first trimester screening?
A
Biochem - bHCG, PAP-A
USS
5
Q
What are the advantages of 1st trimester vs 2nd trimester screening?
A
Accurate dates
Can found more anatomically
Less emotional trauma if terminating
Less delay between next pregnancy
6
Q
What are some disadvantages of 1st trimester screening?
A
Expensive equipment and experienced personnel
Little time to acknowledge pregnancy
Many aneuploidies would spontaneously abort
7
Q
What is pick up rate of the main DS screening methods?
A
Maternal age 33%
2nd Trimester screening 60-70%
1st Trimester combined screening 90%
Free fetal DNA 99%
