First Trimester Screening

( 10 to 14 Weeks )
- Double Marker Test 11 to 14 Weeks

A screening test identifies people at risk for a disorder in unselected population
Why Screen for Down's
-Commonest aneuploidy
- Morbidity High
-0.6-4.1 per 1000 between age
-70% occurs in women <35 years

Incidence of Aneuploidy
Trisomy 21-1 in 800
Trisomy 18-1 in 10000
Trisomy 13->1 in 10000

Types of screening
1. Combined screening
2. Sequential screening
3. Contingent screening
4. Integrated screening

Which is Good Screening test
Those test dives detection Rate 75% and above, FPR 5%

Screening Method Detection of T21 FPR 5%
Double Test 30
Triple Test 60-65
Quadruple Test 65-70
1st Trimester NT 70-75
1st Trimester Pappa-A,Free B HCG 60-65
NT,PAPP-A, Free beta HCG 80-85
Integrated 85-90

1. Combined Screening
- USG + Biochemistry

2. Sequential Screening
- Risk assessment in two stages
- All have combined screening & give results
- Only screen negative group separated & offer a quadruple screening
- First trimester risk used when calculating final risk

11-13+6 weeeks PAPPA-A +BHCG.

15-19 weeks AFP+BhCG+UE3+inhibinA

3. Contingent Screening

All have combined screening, then 3 options

- High Risk-Invasive Diagnosis
- Moderate Risk Quadruple Screening
Low Risk-No further screening
High Risk - 1 in 50 -CVS
Low Risk - 1 in 1000 no further test
Internediate Risk - 1 in 50-1000
Offer Quadruple screening

4. Integrated Screening ( Best screening model )

- Screening happens in two stages
- Single risk assessment after 15 weeks
- After 1st Trimester screening, no result is given to patient
- Patient is asked to come again for 2nd Trimester screening

DR-96.96% FPR-3%

A. Monochorionic Twins
- Identical Risk for each fetus
B. Dichorionic Twins
- Separate risk for each fetus
C. For triplets and higher multiples
- Risk based on USG markers alone
D. Vanishing Twin
- No Fetal pole-Singleton

Second Trimestr Screening

( 15 TO 21 Weeks )
-Quadruple Marker Test

FAQ & Answers

Pregnancy can be seen on a scan from the 6th weeks (halfway through your first trimester), but doctors recommend these early scans to be done between 7th to 12th weeks to ensure that your baby is normally growing inside you.
First trimester ultrasound examination is done to evaluate the presence, size and location of the pregnancy, determine the number of fetuses, and estimate how long you've been pregnant (gestational age)
Having multiple ultrasound examinations during pregnancy is unlikely to cause any lasting harm to the developing fetus, according to a new study that confirms the long-term safety of the commonly used procedure.
A review of over 50 medical studies shows that ultrasounds do not pose any danger to moms or fetuses. They do not cause birth defects, childhood developmental or intellectual problems, or cancer.