Genetic Screening

Question 1

what’s included in integrated screening

Answer 1

1st trimester screen + quad screen

- nuchal translucency measurement

Question 2

advantages of integrated screening

Answer 2

increased detection of aneuploidy

Question 3

disadvantages of integrated screening

Answer 3

fewer options due to timing of results

- first trimester termination is safer and less ethically challenging than a >20wk fetus

Question 4

what is sequential screening

Answer 4

includes first trimester screen results

• if NT and analyte indicate higher risk of aneuploidy, then diagnostic test or cell-free DNA testing offered
• if negative (low risk), then quad screen offered in second trimester

Question 5

if nuchal translucency and analyte testing indicate higher risk of aneuploidy in first trimester, what do you do?

Answer 5

order cell-free DNA or diagnostic test (amniocentesis)

Question 6

use of first trimester ultrasound

Answer 6

determine dates, number of gestations, screen for aneuploidy

Question 7

use of second trimester ultrasound

Answer 7

look for anatomic malformations/structural anomalies or ‘markers’ of aneuploidy
- done between 18 and 22wks

Question 8

what is cell-free DNA

Answer 8

small amounts of fetal DNA can be detected in maternal blood

- screen for aneuploidy as early as 10wks til term

Question 9

cystic fibrosis carrier testing

Answer 9

CF genetic mutations vary, with highest prevalence in whites of Northern European descent (1/25)
- offered to all patients in first trimester with appropriate counseling

Question 10

what should be offered with all genetic screening?

Answer 10

information, genetic counseling, and options regarding their pregnancy (parenting, adoption, termination)