Card Set Information
Who might benefit from genetic testing/counseling?
Mother or father w/a genetic condition
FH of genetic disease
Previous child with
: retardation, anomalies, dysmophic features
AMA (adv mat age)
at risk ethnic group
What are the main goals of prenatal genetic screening?
(risk not affected by parental age)
Identify fetuses with aneuploidy
(risk increases with age)
When does the neural tube close?
What are some DS characteristics?
Flat nasal bridge
Small head with flattened occuput
wide spaced eyes with epicanthal folds
short stubby fingers and simian crease
ITA (Hyperglycosolated HCG)
Produced early (peaks at 9 wks)
↑ in DS, twins, Trisomy 22
↓ Trisomy 18, 13, preeclampsia
↓ levels :
(Maternal serum Alpha Fetoprotein)
abdominal wall defects
UE3 (Unconjugated estriol)
Low levels ALL ABNORMAL
Inhibin A (Dimeric inhibin A)
High levels: Trisomy 21
Low levels: PCOS
What are MOM (multiples of the median)
Indicated how far a result is from the median of all pregnancies at that Gestational age
1.0 = NORMAL
(risk is never reported as "zero")
When are MOMs adjusted
by ethnic group
for maternal weight
What is a common reason for an abnormal MSAFP?
1st TM screening for Trisomy 21
1. Maternal Age
4. Nuchal Translucency
2nd TM screening for Trisomy 21
3. Unconjugated estriol (uE3)
4. ITA or DIA
What is FNT (fetal nuchal translucency) used for and when is it done?
First trimester screening tool (12-13 wks) to identify
Trisomy 18, 21
Fetal Cardiac anomaly
Fetus compensates for delayed lymphatic connections by forcing excess drainage into nuchal area
What does the quad screen detect?
CG and In
MSAFP & uE3
: AFP, HCG, ue3
What is the optimal time for CVS?
What happens with an "integrated approach" to screening?
Everyone receives screening in 1st and 2nd TM
No report given after 1st TM screen
After 2nd TM a
combining both values is reported.
High risk (>1:270) gets amnio
NO ONE IS DIAGNOSED IN 1ST TM
Which screening option is the optimal approach?
What is the contingency approach?
Act on results of 1st TM
(>1:30) - - CVS
(1:30 to 1:1500) 2nd TM Quad
Very low risk
(1:1500), no further testing
75% only get 1st TM screening
Explain the Sequential Approach..
Get 1st TM screen - - Act on results
High risk (>1:30) - Offer CVS
NL risk - 2nd TM Quad screen
Combine results reported
Amnio offered if risk >1:270
Bottom Line: 98% receive 2nd TM Quad screen
What is the next step after getting a POSITIVE test result?
Ensure the dates are correct.
Based on U/S or LMP
What test has the best Tri 21 detection rate?
Quad screen + genetic U/S
(90% detection rate)