Prenatal Diagnosis

Question 1

What is quadruple maternal serum screening?

Answer 1

Checks levels of hCG, AFP, uE3 and inhibin A

Question 2

When can amniocentesis be performed?

Answer 2

After 15 weeks gestation because of the risk of membrane rupture

Question 3

What is chorionic villus sampling?

Answer 3

Taking a small sample of placenta abdomally between 11-15 weeks

Question 4

What is the main limitation of direct analysis of chorionic villus sampling?

Answer 4

Direct analysis examines trophoblast cells of placenta.

Trophoblast cells are rapidly dividing cells so this form of CVS analysis is more vulnerable to mitotic errors

Question 5

What is chromosomal mosaicism?

Answer 5

When two or more abnormal cell lines are detected in 2 or more cultures from the same individual

Question 6

What is pseudomosaicism

Answer 6

When one or two abnormal cell lines are detected in a single culture from the same individual

Question 7

What is uniparental disomy?

Answer 7

Fetus inherited 2 copies of 1 chromosome from the same parent

Question 8

When is fetal DNA present in the maternal blood in measurable quantities.

Answer 8

10 weeks gestation

Question 9

What is non-invasive prenatal testing?

Answer 9

Fetal DNA from the maternal blood is extracted and sequenced to check for chromosomal abnormalities