- The document discusses first trimester screening (FTS), which involves an NT scan and serum biochemistry between 11-13.6 weeks of pregnancy. - FTS allows for early prediction, prevention, diagnosis and management of complications like aneuploidies, preeclampsia, fetal growth restriction, and preterm birth. - The NT scan measures nuchal translucency thickness, which is increased in fetuses with chromosomal abnormalities. Combined with blood tests, FTS can assess risk for conditions like Trisomy 21, 18, 13, preeclampsia and more.

1. 11-13.6 WEEKS SCREENING :
NT SCAN & S. BIOCHEMISTRY
FTS : FIRST TRIMESTER SCREENING
PAST, PRESENT AND FUTURE
FAQs
Dr. Nisheeth M. Oza

2. Dr. Nisheeth M. Oza
M.D., D.G.O., F.C.P.S., D.N.B., (M.N.A.M.S.) (OBGYN)
D.A., M.B.B.S., Dip. YAN
Obstetrician, Gynaecologist, Infertility Consultant,
FMF Certified Ultrasonographer (FMF ID 145907)
Licensed for Aneuploidy Screening NT, NB, DV, Cervix & PIH Screening.
Diploma in Yoga, Ayurveda & Naturopathy
Dr. Oza’s Hospital 87/7, Panvel 410206, Maharashtra India.
Email : drnmozas@gmail.com
Website : drozashospital.com
YouTube : DrOzaConnects

3. In last 30 years, there have been a lot of developments in FTS,
which have inverted the pyramid of Antenatal Care.
Previously one would only come to know about complications in 3rd
Trimester when pregnant women developed Pre-eclampsia or FGR or
had Preterm Birth or after delivery would know that the Newborn had
Down Syndrome or a major structural abnormality.

4. Now, instead of waiting helplessly till third trimester, the focus has shifted to
11-13.6 weeks Screening, with the opportunity for prediction, prevention,
early diagnosis & proactive management of such complications of pregnancy.

5. WHAT TO SCREEN FOR? WHY SCREEN?
1] FOR ANEUPLOIDY e.g. Trisomy 21, 18, 13 :
• Many abort , few have IUFD (Stillbirth).
• Trisomy 18, 13 : Survive only for few hours or days after birth.
• Trisomy 21 : may live upto 49 years, but MR, health problems, financial burden.
2] FOR PRE-ECLAMPSIA & FGR :
• PE – Increased Maternal Mortality, Morbidity.
• FGR- Increases IUFD (Stillbirth), MAS, Neonatal Morbidity.
3] FOR PRETERM BIRTH : Increased Neonatal Mortality, Morbidity.
4] SELECTED CONGENITAL ANOMALIES DETECTABLE AT 11-14 WEEKS :
• Only 10 out of 100.
• Counsel : Compatible with life? Surgery required? Prognosis. Decision making.

6. DEFINITION OF NT & ITS IMPORTANCE
• Definition : NT is the sonographic appearance of collection of fluid
under the skin behind the neck of the fetus in the First Trimester of
pregnancy.
ITS IMPORTANCE IN SUSPECTING ANEUPLOIDY
Median NT
Normal (Euploid) group 2.0 mm
Trisomy 21 3.4 mm
Trisomy 13 4.0 mm
Trisomy 18 5.5 mm
Turner’s Syndrome 9.2 mm

7. EVOLUTION OF FTS
• Trisomy 21 Downs Syndrome was first described in 1866 (156 years ago).
• Trisomy 18 (Edward S.) & Trisomy 13(Patau S.) first described in 1960 (62
years ago).
• Association of advanced Maternal Age & Tri 21 first described in 1909.
First the Invasive Tests were introduced for maternal age > 35 yrs.
1970s Amniocentesis (42 Years ago)
1980 CVS
However, 80% of DS were born to mothers < 35 years and it was not possible
to justify so many invasive tests for age more than 35 years.
Therefore, need for Screening tests was felt, so that these can be offered to
all pregnant women in the First Trimester.
Necessity is the mother of invention.

8. Amongst the SCREENING TESTS available clinically
• 1988 : Triple Marker Test
• 1994 : Double Marker Test
• 2003 : NT Scan Kypros Nicolaides & FMF (work 1992-2002)
• 2005 : Combined Test – NT + Double Marker Test
• 2008 : Quadruple Marker Test
• 2008 : NIPS

9. EVOLUTION OF NT SCAN, FMF, Courses,
Certification, License
• 1866 – John Langdon Down – Tri 21 – Skin appears to be too large (thick) for their
body.
• 1992 – BMJ – Kypros Nicolaides – excessive accumulation of subcutaneous fluid
behind fetal neck, which could be visualized by ultrasonography as raised NT in
3rd month of pregnancy.
• This was the game changer.
• He founded Fetal Medicine Foundation in UK in 1995. Extensive research by him,
by FMF & multicenter trials between 1992 & 2002 approved his findings & 11 to
13.6 weeks scan became widely used in 2003.
• FMF did standardization of 11-13.6 weeks’ scan.
• FMF runs Online Courses for each of parameter of FTS, conducts exams, does
Certification for each parameter, & has provision of software, licensing & annual
audit & annual renewal of this license under its strict control.

10. PURPOSE OF THIS SCREENING : AIM & OBJECTIVES
• To screen for Aneuploidy : Trisomy 21, 18, 13.
• To screen for likelihood of developing Pre-eclampsia.
• To screen for likelihood of developing FGR.
• First assessment of the length of Cervix.
• Early detection of certain Structural Anomalies in fetus (10 out of
100).

11. PRETEST COUNSELING :
• Aneuploidy : Deviation from normal Chromosomal make up, be it in
number or structure.
• Trisomy : Presence of an extra Chromosome at a particular pair of
Chromosomes eg. Trisomy 21, 18, 13.
• What if your fetus has increased NT &/or NB is not visualized?
It means greater risk of Trisomy, structural defect, cardiac defect.
Definitive Diagnostic Invasive Test (CVS) is indicated if NT > 3.0 mm.

12. • What if your fetus has normal NT value?
Detection Rate of NT Scan for Trisomy 21(DS) is 80%, so you can add Serum
Biochemistry (Double Marker Test) to increase DR of Tri 21 to 90%.
Addition of other Sonographic markers like absent/hypoplastic NB, reversal
of a wave in DV, TR, may further increase DR of Tri 21 to 95%.
• What if Screening (Ute. Art. PI) shows increased risk for developing PE or
FGR?
You may be offered Tab. Aspirin 150 mg/day as Prophylaxis, from day of
screening till 34 or 36 weeks of pregnancy.
• How is the first assessment of length of Cervix on TVS useful?
It serves as baseline for comparing at time of further assessment of length of
Cervix, may be at time of Anomaly Scan (18-22 weeks)or earlier if indicated
by History.

13. Progressive shortening of length of Cervix or funneling of Cervix or
length < 25 mm on TVS, indicates high risk of Preterm birth/Second
Trimester loss.
So what can be done for that?
1] Cervical Cerclage (Tightening of Os) Operation.
OR
2] Progesterone ( 400 mg vaginally daily at bedtime) till 34 or 36 weeks
of pregnancy.

14. ASSIGNING PRETEST RISK
Before doing the scan, Data is fed from History, like :
• Mother’s age at the time of delivery.
• Race.
• Number of previous children (Parity).
• Previous Miscarriages.
• Aneuploidy in prior pregnancy & which one?
• History of smoking.
• Maternal Diabetes Mellitus.
• Natural or IVF Conception?
• Chronic HT, SLE, APLA Syndrome.
• Did patient’s mother have Pre-eclampsia?

15. FROM EXAMINATION :
• Height in cm.
• Current Maternal Weight in Kg.
From this, Pretest Aneuploidy Risk is assigned by the software ie. FMF
Software.

16. 11-13.6 WEEKS SCAN : PARAMETERS INCLUDED
Scan by trained FMF licensed sonographer or by sonographer following
Criteria laid down by FMF :
• CRL : Accurate GA, Dating.
• NT, NB : For Aneuploidy.
• DV (reversed a wave) : Increased chances of Aneuploidy, Cardiac Defects,
fetal Deaths.
• TR : Increased chances of Aneuploidy, Cardiac Defects.
• Ute. Art. PI : Screening for Pre-eclampsia, FGR.
• Cervix Length (TVS) : Subsequent Scan-Shortening- predict PT Del.
• Detectable Anomaly : 10 out of 100.
• DOUBLE MARKER : PAPP-A, Free Beta-hCG.
• DOUBLE MARKER + PlGF : PAPP-A, Free Beta-hCG, PIGF.

17. DETECTION RATE OF ANEUPLOIDY AND PE
Trisomy 21 DR FPR
Age alone Low
Double Marker Test alone 65% 5%
NT Scan alone (Properly Performed by FMF norms) 80% 5%
NT + Double Marker (Standardized Lab) 90% 5%
NT + Double Marker + NB 93% 5%
NT + Double Marker + NB + DV + TR 95% 3%
Trisomy 18 & 13
NT + Double Marker + NB + DV + TR 75% 5%
PE
Ute. Art. PI (NT Scan) + Double Marker 84% 5%
Ute. Art. PI (NT Scan) + Double Marker + PIGF 93%

18. POST TEST COUNSELING FOR ANEUPLOIDY
• NT > 3mm or Cystic Hygroma : Increased Chromosomal &/or
Structural abnormality. Therefore, Offer Diagnostic Test : CVS < 14
weeks (or Amniocentesis > 16 weeks).
• NT < 3mm : Add Double Marker Test (Combined Test).
• If Low risk (1 n 1000) – Aneuploidy Unlikely – Reassure.
• If High risk (> 1 in 250) – Means statistical likelihood of Chromosomal
abnormality. Offer Diagnostic Test – CVS/Amniocentesis.
• If Intermediate risk (1 in 250 to 1 in 1000) Counsel – consider NIPS.
NIPS report : Low risk – Reassuring.
High risk – Offer Diagnostic Test – CVS/Amniocentesis.

19. • NIPS Screening Test, avoids Invasive Test,
Low risk – reassuring ;
High risk – Offer Diagnostic Invasive Test : CVS, rarely false positive.
After Invasive Test, patient may have some bleeding pv, Miscarriage
rate 1 in 300.
NIPS (cf DNA) DR(Sensitivity) (FPR : 0.04%)
Trisomy 21 99%
Trisomy 18 93%
Trisomy 13 99%

20. POST TEST COUNSELING FOR PRE-ECLAMPSIA & FGR
Low risk – reassure – Routine Antenatal Care.
High risk – Offer Tab. Aspirin 150 mg/day till 34-36 weeks.
POST TEST COUNSELING FOR PRETERM BIRTH
If previous history of Preterm Birth or HSO Insufficient Cervix or Cervix
Length < 25 mm on TVS or Shortening noticed in subsequent scans :
OFFER
1] Cervical Cerclage : Tightening of OS operation. Or
2] Progesterone 400 mg/day vaginally till 36 weeks.

21. POST TEST COUNSELING FOR STRUCTURAL ANOMALIES
IF ANY DETECTED
• 10 out of 100 are detectable.
Eg. - Anencephaly (Absence of Forebrain)
- Acrania (Absence of Skull)
COUNSELING :
• These two are uniformly lethal, cannot survive after birth.

22. For other Anomalies :
• Associated Chromosomal abnormalities–confirm by Invasive Test-CVS.
• Brief explanation about the anomaly.
• Its natural course, during pregnancy & after birth.
• Need for surgery after birth.
• Prognosis : Quality of life, Level of disability. Long term Outcome.
• Help in nondirective manner. Help in decision making.
• Management respecting couple’s informed choices.

23. COST OF VARIOUS SCREENING TESTS IN NAVI MUMBAI TODAY
TEST COST IN INR
NT Scan 2,500/-
Double Marker Test 2,500/-
Double Marker Test + PIGF 3,500/-
NIPS (BASIC) 13,000/-
LABORATORY COST OF DIAGNOSTIC TESTS
CVS 15,000/-
Amniocentesis 15,000/-

24. FOLLOW UP AFTER DIAGNOSTIC TEST CONFIRMS ANEUPLOIDY
• Non-directive Counseling – Natural history during pregnancy, after
birth.
• Survival after birth.
• Prognosis.
• Informed Decision Making.

25. FOLLOW UP AFTER INCREASED NT, but NORMAL
KARYOTYPE (CVS)
• Incidence of structural defect in this group is higher.
• Repeat Ultrasound at 15 weeks & Anomaly Scan at 18-22 weeks.
• Fetal 2-D Echo at 22-24 weeks.
FOLLOW UP OF MAJOR STRCTURAL ANOMALY &
CONTINUING PREGNANCY
• Multidisciplinary Team Approach.
• Delivery in Tertiary Care Centre with high quality Neonatal Care
available.

26. FAQs AFTER FTS : 11-13.6 WEEKS SCREENING
1] NT > 3 mm – Increased chromosomal & structural abnormality – why
not do MTP directly?
• In certain % of cases, NT may resolve after 14 weeks – Normal
Outcome. NT scan is a screening test.
• Diagnostic Test (CVS or Amniocentesis) is important for KT, important
to help parents in decision making & also define recurrence risk.
2] NT > 3 mm & major structural anomaly, why not do MTP directly?
• Diagnostic Test – find out Etiology of Increased NT & calculate
recurrence risk of that condition.

27. 3] FTS is low risk, so is everything fine?
• Congratulations. FTS has shown low risk, which is quite reassuring.
Very very small % of false negative may be there.
Friends, as far as structural anomalies are concerned at this stage, CRL
is only 6 cm & only 10 out of 100 anomalies can be detected at this
stage, so Anomaly Scan at 18-22 weeks is the next step. Some evolving
anomalies can be detected in 3rd trimester/after birth.
4] What will be the Recurrence Risk of Aneuploidy/Structural Anomaly?
• Depends on the Aneuploidy or Structural Anomaly Diagnosed.
5] What is the role of Quadruple Marker Test in Screening?
• It might have some role in those who missed FTS for some reason.

28. FUTURE OF FTS
1] Will NIPS replace NT Scan (11-13.6 weeks scan)?
• No, NIPS can only predict Aneuploidy risk, NT Scan can do 4 more
things.
2] Will NIPS replace Dual Marker Test?
• Yes it will, as it has higher DR (Sensitivity), When? As soon as the cost
comes down.
3] FUTURE WILL BE ‘SUPPEMENTARY FTS or TESTING’ ie. NT Scan +
NIPS.

29. Remember 3 things :
1] For FTS, proper Pre Test & Post Test Counseling & following a
protocol are very important.
2] FTS today is NT + Double Marker Test.
3] FTS tomorrow will be NT + NIPS.

30. THANK YOU