role of usg in IUGR detection and management

1. ROLE OF ULTRASOUND IN IUGR
Under guidance of
Prof Dr Jayashree Mohanty , (HOD , Dept Of Radiodiagnosis, SCB MCH
)
Asso Prof Dr Basanta Manjari Swain, (Dept Of Radiodiagnosis, SCB
MCH )
Asst Prof Dr Mamata Singh, ( Dept Of Radiodiagnosis, SCB MCH )
Asst Prof Dr Pooja Mishra, ( Dept Of Radiodiagnosis, SCB MCH )
`
Asst Prof Dr Shantibhusan Das,( Dept Of Radiodiagnosis, SCB MCH )
BY DR CHIDANANDA PATRO, 3RD YR JR
DEPT OF RADIODIAGNOSIS, SCB MCH CUTTACK

2. SGA
 decrease fetal weight below the 10th
percentile for gestational age or 2 SD below
the mean for GA as determined through an
ultrasound.

4. SIGNIFICANCE OF SGA DIAGNOSIS
 High mortality
 Half of them surviving have serious short
term and long term morbidity , MAS,
pneumonia , metabolic disorders

5.  Being small for gestational age is broadly
either:[4]
1.Being constitutionally small, ( no maternal
pathology, normal UA, MCA)
2.Intrauterine growth restriction, also called
"pathological SGA"

6. TYPES OF IUGR
Symmetric(20%)
Asymmetric(80%)
 1.all parameters ↓ 1.brain spared
 2.early onset 2.late onset
 3.etiology-chromosomal, 3.etio –utero
TORCH,Cong Malformation placental
insuff
 4.poor prognosis 4. favourable

7. APPROACH TO SGA
 1 diagnosis
 2 classification, determine the cause
 3. management- monitoring, deciding time
for delivery

8. FETAL BIOMETRY
 Getting the correct measurement of HC,
BPD,AC,FL
 Getting correct gestational age

9. FETAL WEIGHT PERCENTILE CHART

10. CAUSE

13.  Look for anomalies -Clenched fingers-
trisomy 18 ,Post axial polydactyly - trisomy
13 , Syndactyly - triploidy
 Look for signs of intracranial infections –
ventriculomegaly, hydrops, intracranial
calcifications
 Thick cystic placenta seen in diandric
triploidy

14. SURVEILLANCE
 1. amniotic fluid volume
 2. biophysical profile scoring
 3. fetal doppler

15. AMNIOTIC FLUID
 It’s a marker of chronic stress, often used as
independent indicator of delivery
 Blood shunted to cerebral and coronary
circulations
 Decreased renal perfusion leading to less
urine thus oligohydramnios
 Low fluid has correlation with poor outcome
 IUGR + polyhydramnios ominous
combination high risk of trisomy 18

16. FETAL BIOPHYSICAL PROFILE
 Currently gold standard for evaluation
 Uses 4 usg parameters and NST
 1. fetal movement
 2.fetal tone
 3. fetal breathing movement
 4. Amniotic fluid

17. Fetal biophysical profile

18. LIMITATION
 less reliable in the severely premature fetus
because of lack of brain maturity and should
not be administered before 24 weeks’
gestation
 the biophysical state of the fetus is affected
by administration of corticosteroids, which
may cause depression of fetal breathing and
movement for a few days after treatment

19. MODIFIED BIOPHYSICAL PROFILE
 Includes NST and AFI

20. DOPPLER VELOCITY WAVEFORM
 Identifies the fetus at risk
 Helps in monitoring
 Provides a tool to assess the appropriate
timing of delivery
 Improves pregnancy outcomes

21. UMBILICAL ARTERY
 It is direct reflection of placental flow obliteration
 Can be assessed in 3 sites – placental origin,
fetal abdominal site insertion or in free floating
 Resistance at abdominal site is higher &
progressively decreases towards placental site
 By about 15 weeks of gestation, diastolic flow
can be identified in the UA. With advancing
gestational age, the end-diastolic velocity
increases secondary to the decrease in
placental resistance. This is reflected in
decreases in the S/D or PI

22.  s/d ratio 2-3 in 2nd &3rd trimester
 PI – 2nd trim (1.5 - 2)
 - 3rd trim (1 – 1.5)
 RI – in late 2nd & 3rd around 0.5

24.  Here defective trophoblastic invasion causes
increased placental resistance, hence
decreased forward flow in UA during diastole
 S/D , PI, RI all of them increases
 Changes are seen only when 60% of placental
blood flow is obliterated.
 Eventually diastolic flow reaches zero = AEDF
 Further increase causes reversal= REDF (high
perinatal mortality)

26.  Umbilical Doppler flow measurements are
the most valuable current technique to
distinguish the sick IUGR fetus from the well
IUGR fetus.
 indicates whether an identified SGA fetus is
affected by placental dysfunction or not.

27. UTERINE ARTERIES
 Reflects trophoblastic invasion
 In early pregnancy, the uterine circulation is
characterized by high vascular impedance and
low flow, giving a waveform with persistent end-
diastolic velocity and continuous forward blood
flow throughout diastole. As the trophoblastic
invasion and spiral artery modification proceed,
placental perfusion increases and the
uteroplacental circulation becomes a high-flow,
low-resistance system giving a waveform with
greater end-diastolic flow.

29. When the normal trophoblastic invasion and
modification of spiral arteries is interrupted
there is increased impedance to flow within
the uterine arteries and decreased placental
perfusion, it results in
1. Persistence of diastolic notch beyond 24
weeks
2. Low diastolic flow reflecting as increased PI

31.  presence of a notching in late in pregnancy
is an indicator of increased uterine vascular
resistance and impaired uterine circulation .
 Bilateral notching is more concerning.
 Unilateral notching of the uterine artery on
the ipsilateral side of the placenta, if the
placenta is along one lateral wall (right or
left) carries the same significance as bilateral
notching.

32.  If the PI of both the uetrine artery are normal
patient can be informed that she will most
likely not develop pre eclampsia or IUGR , as
it has 99% predictive value

33. FETAL CEREBRAL CIRCULATION
 MCA is vessel of choice as it is easily
identifiable and easily reproducible
 It reflects cerebral flow
 Normally – high resistance with continous
forward diastolic flow

34.  Mild hypoxia – umbilical artery resistance
increases , no change in blood flow pattern
except mild increased psv
 ↑ hypoxia – aortic chemoreceptor
stimulation→reflex redistribution of cardiac
output→ increased flow to brain (brain
sparing effect)
 Reflected as reduced PI indicating
compromised fetus in utero

36. CEREBRO PLACENTAL RATIO
 To describe placental resistance and cerebral
adaptation Arbielle et al describes cerebral placental
ratio
 t is calculated by dividing the Doppler pulsatility index
of the middle cerebral artery (MCA) by the umbilical
artery (UA) pulsatility index:
 CPR = MCA PI / UA PI
 C:p is constant during pregnancy particularly after 30
weeks & all value less than 1 are abnormal

37. VENOUS CIRCULATION
 Ductus venosus reflects acidosis
 triphasic waveform comprises of:
 S wave: corresponds to fetal ventricular
systolic contraction and is the highest peak
 D wave: corresponds to fetal early
ventricular diastole and is the second highest
peak
 A wave: corresponds to fetal atrial
contraction and is the lowest point in the
wave form albeit still being in the forward
direction

39.  Under hypoxic condition, cardiac
decompensation→↑ right atrial pressure→
reduction of a wave to baseline
 Further hypoxia→ reversal of a wave

42. UMBILICAL VEIN
 Relects myocardial activity
 Normal – monophasic with continous forward
flow
 It is the last vessel to be affected when
hypoxia develops
 During hypoxia heart failure occurs pulsatile
wave pattern with reversal of flow occurs
 Double pulsation signifies severe cardiac
insufficiency

44. FETAL CARDIAC SYSTEM
 Get a 4 chamber view & place the sample volume just
distal to the valve leaflets.
 Normally 2 waves
 E wave -first peak , reflects passive ventricular filling in
early diastole
 A wave –second peak reflects the atrial contraction in late
diastole
 Early in gestation – A > E
 With advancing gestation, early diastole E increases and
reaches late diastole A
 In growth-restricted fetuses, the E/A ratio is higher than
that of normal fetuses controlled for gestational age due
to preload impairment without impairment in fetal
myocardial diastolic function.

46. STAGING AND MANAGEMENT

47. CONTD….
 After reaching 34 wks , no much use of
prolonging pregnancy
 Factors that suggest immediate delivery
depite gestational age
 Severe oligohydramnios
 Evidence of brain sparing , with ominous
doppler study
 Maternal compromise

48. SUMMARY
 Although multiple vessels have been
investigated in FGR, a combination of arterial
and venous vessels is the most practicable
to demonstrate the degree of placental
disease, level of redistribution and degree of
cardiac compromise.
 The umbilical artery, middle cerebral artery,
ductus venosus and inferior vena cava
provide a comprehensive evaluation of these
aspects.

49. Q WHICH AMONG THESE IS BETTER
PREDICTOR OF PERINATAL MORTALITY ?
 MCA PSV
 MCA PI
Answer MCA PSV
Further hypoxia → brain edema→ ↑intracranial
pressure→reversal of diastolic flow→grave