Investigations in First Trimester Pregnancy

For the use of registered medical practitioner only.
D.G.F CME on
11th
April at Leela Ambiance Delhi
Investigations in First Trimester Pregnancy
Contributors
Dr Dipti Nabh & DGF Team Expert
PART 3

Investigations in
First Trimester Pregnancy

Introduction
 Pregnancy is a normal physiological process and any
intervention that is offered to the pregnant or expectant
mother should have known benefits and should be
acceptable to the woman
 Screening in pregnancy is the process of surveying a
population of women with markers and defined screening
cut-off levels, to identify those at higher risk for a particular
disorder
 All pregnant women, regardless of age, should be offered,
through an informed counselling process, the option of a
prenatal screening test for the most common clinically
significant fetal aneuploidies
Source: http://www.fogsi.org/wp-content/uploads/2017/12/tog-conclave-algorithms.pdf as accessed on 2nd March 2018 at 14:06

Antenatal screening
Antenatal screening
Confirm pregnancy (Clinically/
Beta-HCG/ UPT/ Ultrasound)
Viable test (Fetal heart rate)
(Clinical/ Fetal monitor/ USG)
Pregnancy
Maternal weight Urine dipstick+ All
routine blood tests
Maternal blood
pressure (both arms)
(Sitting)
Pregnancy

Investigations in pregnancy
At booking general physical exam heart/lungs/breast/abdomen
• Maternal weight/BMI
• Blood pressure/mean arterial pressure
• Urine dipstick (albumin, sugar)

Antenatal Checklist
First Trimester Recommended Preferable
Weight BMI
Blood Pressure Mean arterial pressure
Hemoglobin Complete blood count/ Peripheral smear/ Hb/
Electrophoresis/ HPLC
Blood group ABO & Rh
(both partners)
Urine routine MSU + Culture
VDRL/ Hep B/ HIV HCV/ Rubella IgG
TSH Thyroid function test/ Thyroid Antibodies,
Vitamin D
DIPSI Test 75 grams 2 hrs blood
sugar
HbA1C/ OGTT/ 6 point blood sugar test
Dating scan+ NT, Double marker
(free beta HCG+ PPAA’) Contingent
screen
Cervical length, Uterine artery doppler, NIPT,
Placental Growth factor (PLGF)
Per speculum exam Pap smear, bacterial vaginosis and Chlamydia
screen

Screening for thalassemia should be offered to all
women as early as possible in pregnancy (ideally by 10
weeks) and arrangements for appropriate referrals
Rational for thalassemia screening
 Universal screening – Recommended in high risk population such as
India
 Screening of husband needed if wife is carrier
 If both partners are carriers then CVS or amniocentesis
recommended
Recommended Investigations: Thalassemia

Recommended Investigations:
Asymptomatic Bacteriuria
Urinalysis of Midstream Urine to rule out asymptomatic
bacteriuria
Rational for this investigation
 25-30% progress to symptomatic infection
 Can result in acute pyelonephritis, acute cystitis and Urethritis
 Commonest isolated organism is E coli
 One of the commonest cause of preterm labor and a significant
burden on healthcare resources

Hepatitis B
Serological screening for hepatitis B virus should be offered to
pregnant women so that effective postnatal interventions can be
offered to infected women to decrease the risk of mother-to-child
transmission
Rational for hepatitis B
 Vertical transmission (mother to infant) of infection occurs in ninety percent of
pregnancies where the mother is hepatitis B e antigen positive and in about ten
percent of surface antigen positive, e antigen negative mothers. Most (>90%) of
infected infants become chronic carriers
 Immuno-prophylaxis for infants born to infected mothers, including hepatitis B
vaccine and hepatitis B immune globulin
 Routine vaccination of all infants with the hepatitis B vaccine series, with the first
dose administered at birth

Recommended Investigations: HIV
Pregnant women should be offered screening for HIV infection early
in antenatal care because appropriate antenatal interventions can
reduce mother-to-child transmission of HIV infection
Rationale
 Can happen at any time during pregnancy, labor, delivery, and
breastfeeding
 If a woman is treated for HIV early in her pregnancy, the risk of
transmitting HIV to her baby can be 1% or less
 With current treatment, many people who have perinatal HIV are living
long into adulthood

Recommended Investigations: Thyroid
Screening
Routine Thyroid screening – for treatment of clinical and
subclinical Hypothyroidism
Rationale
 Demand for thyroid hormone increase during pregnancy
 Fetal thyroxine is obtained from Mother in first trimester as fetal
thyroid only starts functioning in second trimester
 Subclinical Hypothyroidism – High TSH with normal Free T4 level
 Subclinical Hypothyroidism – commonest form of Hypothyroidism in
pregnancy

Recommended Investigations: Thyroid
Screening
 Associated with Adverse Pregnancy outcomes
 Miscarriage
 Anemia in Pregnancy
 Abruptio placentae
 PPH
 Preterm delivery
 Increased incidence of RDS
 Untreated hypothyroidism can result in suboptimal neuro intellectual
development in Offspring
 Levothyroxine supplementation essential for Hypothyroid mothers
 Uncontrolled hyperthyroidism in pregnancy is associated with an increased risk
of severe preeclampsia
 There is a 4 fold increase in low birth weight
 PTU treatment is recommended in hyperthyroidism in pregnancy

Preeclampsia screening
Blood pressure and urinalysis at each antenatal visit for Preeclampsia screening
ASPRE Trial: Aspirin For Evidence Based Pre eclampsia
Prevention
All women at routine visit at 11 -13+6 weeks offered screening for PE by means of
an Algorithm – (BAYES)- MAP
PAPPA
UA-PI
PGF
MATERNAL FACTORS
150 mg/day of Aspirin was administered form 11-36 wks in high risk women for
preterm pre-eclampsia
Source: Rolnik DL et al. ASPRE trial: performance of screening for preterm pre-eclampsia. Ultrasound Obstet Gynecol. 2017 Oct;50(4):492-495.

Preeclampsia screening
RESULTS:
– Study population of 25797 pregnancies included 180 (0.7%) cases of preterm
PE, 450 (1.7%) of term PE and 25167 (97.6%) without PE
– In combined first-trimester screening for preterm PE with a risk cut-off of 1 in
100, the DR was 76.7% (138/180) for preterm PE and 43.1% (194/450) for
term PE, at screen-positive rate of 10.5% (2707/25797) and FPR of 9.2%
(2375/25797).
CONCLUSION:
– Performance of screening in the ASPRE study was comparable with that of a
study of approximately 60000 singleton pregnancies used for development of
the algorithm; in that study, combined screening detected 76.6% of cases of
preterm PE and 38.3% of term PE at a FPR of 10%

Screening For
Aneuploidy

• Debates- 1.How To screen:
Biochemical screen vs USG screen
(wald vs Nicolaides)
2. When To screen
First Trim Screen vs Second Trim Screen
• High risk screening-1. Age above 35
2.Previous h/o DS
Controversies
Screening For Aneuploidy

Screening Test:-
First Trimester Screening
1.10 0/7—13 6/7 wks
2.crl – 45----84mm
3.NT scan
4.Analyte Levels–PAPP A & Beta HCG
5.Maternal factors

Maternal Factors
• Maternal Age ( DOB )
• Race
• Gestation Age ( CRL )
• Multiple Pregnancy
• H/O Down Syndrome baby
• Maternal Weight (kg)
• IDDM
• Exogenous HCG
• H/O Bleeding PV
• Blood values (MOM) + NT value

Screening Test:-
• First Trimester screening
• Nuchal Translucency - Fetal Medicine Foundation
Criteria
• 11 to 13 weeks 6 days
• CRL 45 - 84mm.
• Fetal head + thorax occupy the whole screen
• Mid-sagittal view of the face obtained
• Fetus in neutral position, head in line with spine
• Distinguish between fetal skin and amnion
• Widest part of translucency must be measured
• Calipers placed ON the lines
• Average of three

Cicero et al. Lancet 358; 2001
Screening Test:-
USG marker : Nasal Bone (11wk - 13wk 6 day)
First Trimester screening

Screening Test:-
Second Trimester Screening
1.Quadruple screening-
15 0/7 to 19 0/7 wks
No specialized USG
Add information of risk of open NTD
Analyte levels – AFP, HCG, Inhibin, Unconj Estriol
Maternal factors

Screening Test:- Biochemical
Second Trimester Screening
2 Penta Screen
Includes Quad screen markers and
hyperglycoselated hcg
3 Triple screen
HCG , AFP, Unconjugated Estriol

Biochemical Screening
Screening method Detection Rate FPR
Mat age alone 30% 5%
Double Test
(AFP+HCG)
58% 5%
Triple Test
(AFP+HCG+E3)
69% 5%
Quadruple Test
(AFP+HCG+E3+In)
76% 5%
*FPR = False Positive Rates

• Combined First and Second Trimester screening
• 1. Integrated screening
First Trimester NT and analyte screening
Followed by second Trimester Quad screening
and receives a single test result in second
Trimester
• 2.Serum Integrated screening – accurate NT
measurement is not possible
Limitations

Low risk High Risk ( 5 % )
Quad screening
Continue
Do NIPS
CVS / Amnio
Diagnostic
Sequential screening- Step wise3.
Second Trimester
Double Marker +NT + Others

Sequential screening- Contingent4
High Intermediated low
CVS
NIPS
QUAD SCREENING
Reassure
Second Trimester Anomaly scan
Double Marker +NT + Others
Second Trimester Anomaly scan

Screening Test:- Ultra sonographic
Markers
• Older : (2nd trim)
• CPC, echogenic bowel, golf ball, ventriculomegaly, pelvicalycial
dilatation, short femur, double bubble, sandal gap etc.
• Newer : (1st trim)
• NT, nasal bone, faciomaxillary angle

• CVS: from 11 weeks
• Amniocentesis: from 15 weeks
• Miscarriage: Fetal loss rates comparable 0.5-1% (Cochrane (2003))
• Culture failure: Higher with CVS due to Placental mosaicism or Lower
resolution chromosome band
Problems with the Conventional Approach
• Sensitivity : 80 - 90% in good hands & machine
• False positive : 3-6% (high amnio rate)
• Late diagnosis: Earliest 13-16 weeks

NIPT:- Noninvasive Prenatal
Testing
• Evaluates short segments of DNA in maternal Blood
• Foetal component of cell free DNA is released in
maternal circulation from placental cells undergoing
apoptosis
• Comprises 3-13% of total cell free DNA
• Detected from 10 wks till Term
• Decreases immediately after child Birth
• Also used to detect- sex of foetus
• Rh+ve Foetus in Rh- ve Mother

• All women should be offered a 1st trim USG, regardless
of their intention to undergo Down screening
• Following normal scan, there are 3 options :
• * NIPS as a first line screening test
• * Direct invasive test when background risk is high
• * Combined test and NIPS when screen +ve
ISUOG Consensus Statement 2014

ISUOG Consensus Statement 2014
No need of Combined
screen or Quad screen
No need for amnio
Continue
Do NIPS
Low risk High Risk
CVS / AmnioContinue
Combined test and risk calculation (ISUOG)

Carry Home Message
No need for Quad Screen
TIFA
18 to 21 weeks
Targeted Imaging of
Foetal anamolies
NIPS
Quadruple Screen
Low risk High Risk
CVS / Amnio
FISH
Karyotyping
Micro Arrays
Continue
Combined test (N.T. Scan and Dual Marker)
11-13 0/6 weeks

33
Disclaimer: The scientific content is intended to be used for Healthy Pregnancy workshops initiated by Abbott India Limited for awareness/
educational purposes of healthcare professionals in relation to gynaecology and obstetrics. The content is confidential and proprietary to
Abbott. Although great care has been taken in compiling the content, Abbott India Limited and its servants are not responsible or in any way
liable for the accuracy of the information, for any errors, omission or inaccuracies, or for any consequences arising therefrom. Abbott India
Limited shall not be held liable for any error, omissions and consequences, legal or otherwise arising out of any information provided in this
content. Opinions expressed do not necessarily reflect the views of Abbott India Limited.
INDDUSTO18151221Mar2018
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Investigations in First Trimester Pregnancy

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