Antenatal Screening

Question 1

maternal serum markers in Down’s syndrome

Answer 1

BhCG, PAPP-A and AFP

Question 2

what is the positive result of serum markers for down’s

Answer 2

BhCG - raised
PAPP-A - lowered
AFP - reduced

Question 3

in what abnormality is AFP raised

Answer 3

neural tube defects

Question 4

risk of down’s in a 45 year old mother

Answer 4

1 in 30

Question 5

general risk of down’s

Answer 5

1 in 700

Question 6

how is nuchal translucency measured

Answer 6

size of pad at nape of fetal neck on ultrasound

Question 7

what an abnormally high nuchal translucency tell you

Answer 7

that there is fetal heart failure, this has a strong association with a chromosomal abnormality

Question 8

when is down’s syndrome screening done

Answer 8

10-14 weeks

Question 9

initial down’s syndrome screening

Answer 9

US and maternal blood tests for AFP, PAPP-A and BhCG

Question 10

further down’s syndrome testing

Answer 10

CVS, amniocentesis and non-invasive prenatal testing

Question 11

what is CVS

Answer 11

chorionic villus sampling - a sample of the placenta blood

Question 12

risk of CVS and amniocentesis

Answer 12

miscarriage (1-2% in CVS and 1% in amniocentesis)

Question 13

what supplement is taken in cases of high neural tube defect risk

Answer 13

folic acid

Question 14

purpose of 2nd trimester scan

Answer 14

find fetal abnormality

Question 15

give 3 examples of structural defects that on be identified on a 22 week scan

Answer 15

exopthalamus, cleft lip, omphalocele

Question 16

maternal infections you would screen the baby for

Answer 16

hep B, rubella, syphilis, HIV

Question 17

effect of rubella on baby

Answer 17

congenital rubella syndrome - mental handicap, blindness, deafness, heart defects

Question 18

when is anaemia screened for

Answer 18

at booking and 28 weeks

Question 19

purpose of isoimmunisation screening

Answer 19

identify rhesus disease

Question 20

pathophysiology of rhesus disease

Answer 20

mother is rhesus -ve and baby is rhesus +ve. Baby RBC cross into mother’s circulation. Mother produces anti-D antibodies which attack fetal RBCs. Miscarriage after 12 weeks.

Any subsequent pregnancies the mother already has these antibodies

Question 21

if baby is breech presentation after 36 weeks what can be done

Answer 21

ECV (external cephalic version)

Question 22

what % of neural tube defects will be identified at 2nd trimester scan with bloods

Answer 22

90%