Antenatal Screening Flashcards
maternal serum markers in Down’s syndrome
BhCG, PAPP-A and AFP
what is the positive result of serum markers for down’s
BhCG - raised
PAPP-A - lowered
AFP - reduced
in what abnormality is AFP raised
neural tube defects
risk of down’s in a 45 year old mother
1 in 30
general risk of down’s
1 in 700
how is nuchal translucency measured
size of pad at nape of fetal neck on ultrasound
what an abnormally high nuchal translucency tell you
that there is fetal heart failure, this has a strong association with a chromosomal abnormality
when is down’s syndrome screening done
10-14 weeks
initial down’s syndrome screening
US and maternal blood tests for AFP, PAPP-A and BhCG
further down’s syndrome testing
CVS, amniocentesis and non-invasive prenatal testing
what is CVS
chorionic villus sampling - a sample of the placenta blood
risk of CVS and amniocentesis
miscarriage (1-2% in CVS and 1% in amniocentesis)
what supplement is taken in cases of high neural tube defect risk
folic acid
purpose of 2nd trimester scan
find fetal abnormality
give 3 examples of structural defects that on be identified on a 22 week scan
exopthalamus, cleft lip, omphalocele
maternal infections you would screen the baby for
hep B, rubella, syphilis, HIV
effect of rubella on baby
congenital rubella syndrome - mental handicap, blindness, deafness, heart defects
when is anaemia screened for
at booking and 28 weeks
purpose of isoimmunisation screening
identify rhesus disease
pathophysiology of rhesus disease
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
if baby is breech presentation after 36 weeks what can be done
ECV (external cephalic version)
what % of neural tube defects will be identified at 2nd trimester scan with bloods
90%