This document provides an overview of Doppler ultrasonography in obstetrics. It discusses the prerequisites for Doppler studies including the ultrasound machine capabilities and patient preparation. It describes the indications for Doppler including fetal growth abnormalities and maternal risk factors. It examines in detail the various fetal and maternal vessels that can be assessed by Doppler including the umbilical artery, middle cerebral artery, and uterine arteries. It outlines the normal and abnormal waveforms seen in each vessel and their clinical significance.

1. DOPPLER IN
OBSTETRICS
Dr. Anil Rawat(MD)
Assistant professor
King George Medical University Lucknow

2. FETAL
CIRCULATION

3. INTRODUCTION
• Unique, non-invasive method to investigate the fetal
hemodynamic state
• Used to investigate fetal, feto-placental, & utero-placental
circulation
• Doppler ultrasonography (DU) velocimetry of fetal and
uterine vessels is a well-established method for antenatal
monitoring.
• Certain Doppler waveforms indicating circulatory changes-
predict adverse perinatal outcomes.

4. • introduced in obstetric imaging and fetal monitoring in
1977.
• Fitzgerald et al-first to report noninvasive
demonstration of the umbilical cord (UC) blood flow
pattern and suggested that the umbilical artery (UA)
waveforms could be abnormal in fetuses with IUGR
• DU waveforms not only reflect blood velocity but also
provide information on various aspects of blood flow like
presence and direction of flow, velocity profile, flow
volume, and impedance.
• Among all vessels studied, the UMA and MCA are
relatively easier to access and evaluate and are reported
to be more reproducible.

5. PREREQUISITES FOR
DOPPLER STUDY
The USG machine
• color flow and spectral wave Doppler capabilities
• display the flow velocity scales.
• Estimate peak systolic velocity (PSV), end-diastolic velocity
(EDV)
• Calculate the commonly used Doppler indices i.e. pulsatility
(PI) and resistive (RI) indices and systolic/diastolic velocity
(S/D) ratio
• Probe related: curvilinear probe with frequency range 3-
5Mhz

6. Patient preparation
• Loose clothing.
• Full bladder(in early gestation).
• Position : slightly right or left lateral position to
avoid supine hypotension syndrome secondary
to gravid uterus.
• Nicotine products avoided for two hours, as it
may cause blood vessels to constrict and not
produce accurate results.

7. INDICATIONS
• Abnormalities of growth (both intrauterine growth
restriction(IUGR) and excessive fetal growth
(macrosomia).
• Fetal anomalies (e.g., cystic hygromas, cardiac, thoracic,
diaphragmatic, neural tube, renal, and abdominal wall).
• Fetal hydrops.
• Oligohydramnios and polyhydramnios.
• Bad obstetrics history (e.g., preeclampsia, IUGR,
previous stillborn)

8. • Known maternal risk factors: hypertension,
preeclampsia, diabetes, autoimmune disorders,
thrombophilia
• Abnormally raised MSAFP or increased risk for fetal
chromosomal abnormality.
• Multiple gestation.
• Maternal trauma (fetal-maternal hemorrhage).
• Suspected placental abruption.
• Known maternal isoimmunization( Exposure to
parvovirus B19 In recent years).

9. MATERNAL
VASCULAR
PROBLEMS
DECREASED UTERO-
PLACENTAL-FETAL
PERFUSION
FETAL HYPOXIA
REFLEX
REDISTRIBUTION OF
BLOOD FLOW
VASOCONSTRICTION
VASODILATATION
RESTORATION OF
BLOOD FLOW

10. END RESULTS
• Oligohydramnios
• Decreased abdominal circumference (where the
liver is located)
• Normally growing head
-Asymmetric IUGR-hallmark of chronic,
compensatory fetal hypoxia due to utero-
placental-fetal-vascular insufficiency

11. ANALYSIS OF ARTERIAL VELOCITY
WAVEFORMS
• The ascending limb of the waveform
represents the increase in the velocity
secondary to high P gradient
generated by cardiac systole.
• Produced during each heart
contraction which enables the blood
to be pumped to the vessel thus
generating high velocity and high
waveforms

12. • Descending limb-the blood velocity during diastole (a
relatively passive state after cardiac contraction)
• Determined by downward (distal) resistance and vessel
wall compliance
• More compliant the vessel wall(decreased resistance) --
faster flow (higher velocity)—higher diastolic waveform.
• Indicates better tissue perfusion.
• In pregnancy, there is a progressive decrease in the
placental vascular resistance secondary to a total
increase in the numbers of tertiary system villi and small
arterial channels.

13. • Trophoblastic invasion/destruction of the tunica media
of the spiral arteries--more compliant(less resistant)
vessels
• Increase in the diastolic waveform as pregnancy
progresses to term
• The ascending limb of the waveform (systolic peak) as
brought about by myocardial contractility does not
change significantly with AOG

14. VESSELS EXAMINED
Placental side
Umbilical artery
Maternal side
Bilateral uterine artery
Fetal side
Arterial: Middle cerebral artery
Venous: Ductus venosus and
umbilical
Other less commonly examined
artery are:
Fetal descending aorta
Fetal renal artery

15. UMBILICAL ARTERY
• UMBILICAL CORD: inserts to the placenta, usually
near the center of its fetal surface.
• At term, the UC usually is 1-2cm in diameter and
30-90 cm in length
• Usually has 2 arteries and 1 vein
• Umbilical arterial Doppler assessment is used in
surveillance of fetal well being in the third trimester
of pregnancy.
• Abnormal umbilical artery Doppler is a marker of
uteroplacental insufficiency and consequent IUGR
or suspected pre-eclampsia.

16. UMBILICAL ARTERY
• Doppler indices in the UMA correlate well with the
changes in the peripheral resistance and
volumetric flow when the downstream circulation
(intra-placental vascular resistance) is
compromised by mechanical obstruction.
• The most remarkable influence in the UMA
Doppler indices is that of AOG.

17. Inc no. of vascular channels, tunica media
destruction and trophoblastic invasion
Decreased intraplacental vascular
resistance
Increased blood flow velocity in UMA
Taller diastolic waves EDV waveform
Low SD Ratio ,PI, RI
BETTERTISSUE
PERFUSION

18. METHODS OF UMA
ASSESSMENT
• Free loop of uncompressed cord
• Identify umbilical artery- Use Color Doppler
• Magnify optimally
• Pulsed Doppler gate 1–2 mm
• Gate over single umbilical artery
• The angle of insonation-as low as possible to maximize both systolic and
diastolic components
• At least 5 uniform waveforms
• Absence of fetal breathing and movement during measurement

19. CLINICAL USES
SINGLE UMBILICAL ARTERY
• The most common congenital anomaly of the
umbilical cord
• SUA fetus- 6 times greater risk of congenital
anomalies,15times greater risk of chromosomal
abnormalities
• Isolated SUA has greater placental abnormalities
and hydramnios than 3 vessel cord

20. CLINICAL USES
FETAL GROWTH RESTRICTION
• There is progressive worsening of the UMA flow
velocity due to increasing systemic resistance in
IUGR with risk of stillbirth and asphyxia.
• Use of Doppler studies in SGA and pre-eclamptic
pregnancies has been associated with a reduction in
perinatal mortality.

21. • SIGNIFICANCE OF ELEVATED UMA INDICES
Increased intra-placental vascular resistance
Increased UMA indices
Decreased fetal perfusion
can lead to IUGR later

22. • Characteristics:
• "saw tooth" pattern with flow always in the forward
direction
• progressive decrease in RI and PI due to maturation of the
placenta and increase in the number of tertiary stem villi.
• Fetal breathing-related modulation of arterial pulsatility
Umbilical artery Doppler studies should be avoided during
fetal breathing.

23. NORMAL WAVEFORM
Normal impedance to flow in the umbilical arteries and normal
pattern of pulsatility at the umbilical vein
1STTRIMESTER
2ND TRIMESTER
3RD TRIMESTER
Pulsatile waveform of
umbilical vein is considered
normal in 1st trimester

24. WAVEFORM PARAMETERS
• SD ratio: systolic velocity/diastolic velocity
• PI (Gosling index): (PSV - EDV)/TAV
• RI (Pourcelot index): (PSV - EDV) / PSV
• PSV: peak systolic velocity
• EDV: end diastolic velocity

25. The Doppler indices have been found to
decline gradually with gestational age
(i.e. there is more diastolic flow as the
fetus matures):
S/D ratio mean value decreases with
fetal age
• at 20 weeks, the 50th percentile for
the S/D ratio is 4
• at 30 weeks, the 50th percentile is
2.83
• at 40 weeks, the 50th percentile is
2.18
RI mean value decreases from 0.756 to
0.609
PI mean value decreases from 1.270 to
0.967

26. ABNORMAL WAVEFORMS
Severity of abnormal umbilical artery
waveform
• Class1= reduction in end diastolic flow:
increasing RI values , PI values and S:D
ratios
• Class2=absent end diastolic flow
(AEDF): RI = 1
• Class3=reversal of end diastolic flow
(REDF)

27. SIGNIFICANCE OF
ABSENT/REVERSED FLOW
• AED flow-normal at 18-20 weeks AOG
• AEDV -IUGR in 83% of cases
• Trisomy 18-most commonly associated with AEDV
• The mean duration from AEDV to onset of fetal distress
is 6-8 days
• Increased risk of neonatal thrombocytopenia,
necrotizing enterocolitis
• Maternal hydration, bed rest, oxygenation, and
antihypertensive drugs were noted to improve AEDV

28. • Reversed EDV represents the most extreme
form of intra-placental vascular resistance
• Diagnosis to distress interval is 4-6 days with
perinatal mortality rate of 50%

29. MIDDLE CEREBRAL ARTERY
• The middle cerebral artery
(MCA) is one of the three
major paired arteries that
supply blood to the brain.
• MCA arises from the internal
carotid artery (ICA) as the
larger of the two main
terminal branches (MCA and
Anterior cerebral artery).

30. MCA doppler is important part of assessing
• fetal cardiovascular distress
• fetal anemia or
• fetal hypoxia.
It is also used in the additional work up of
• Intra-uterine growth restriction (IUGR)
• Twin to twin transfusion syndrome (TTTS)
• Twin anemia polycythemia sequence (TAPS)

31. IDENTIFICATION
• The fetal head-transverse
plane.
• An axial section of the
brain, including the thalami
and the sphenoid bone
wings, should be obtained
and magnified.
• The MCA vessels-found
with colour Doppler
overlying the anterior wing
of the sphenoid bone near
the base of the skull.

32. • The reading should be
obtained close to its origin
from the internal carotid
artery as the systolic velocity
decreases with distance from
the point of origin of this
vessel.
• An angle of insonation of <15°
should be used; an angle that
approximates 0° can be
achieved by moving the
transducer on the maternal
abdomen.

33. WAVEFORM PARAMETERS
• Fetal MCA pulsatility index (PI)
• Fetal MCA peak systolic velocity (PSV): the
highest velocity should be recorded
• Fetal MCA systolic/diastolic (S/D) ratio: a
normal fetal MCA S:D ratio should always be
higher than the umbilical arterial S:D ratio.
• Cerebroplacental ratio (CPR): ratio of pulsatility
index of MCA and umbilical artery

34. CEREBROPLACENTAL
RATIO
• The cerebroplacental ratio (CPR)-calculated by dividing
Doppler indices of the MCA by the indices of the umbilical
artery.
• Pulsatility index- most commonly used index.
• This ratio accounts for the interaction of blood flow changes
in the fetal brain as a result of increased placental resistance.
• CPR values <1- abnormal.
• Abnormal CPR values have been associated with increased
risk of adverse perinatal outcomes including stillbirth,
perinatal mortality, fetal distress, neonatal intensive care
admission, and poor neonatal neurologic outcomes.

35. WAVEFORM ASSESSMENT
• In the normal situation, fetal
MCA demonstrates high
systolic velocity and low/absent
diastolic velocity.
• In pathological states this turn
into a low resistance flow
mainly as a result of the fetal
Brain sparing theory.
• Cerebroplacental ratio: >1:1 is
normal and <1:1 is abnormal
NORMAL
IUGR

36. NORMAL MCA FLOW
1ST TRIMESTER
2nd 3rd TRIMESTER

37. TWOWAVES OFTROPHOBLASTIC
INVASION
• 1st wave (6-12 weeks AOG)- invasion
of the spiral arteries within the
decidua
• 2nd wave (16-22 weeks AOG)-
endovascular trophoblasts reaching
the myometrial portions of the spiral
arteries “ballooning of the invaded
spiral arteries”
-decreased resistance to flow, high
diastolic waves with disappearance of
the notch

38. IDENTIFICATION
• the probe is placed
longitudinally in the lower
lateral quadrant of the
abdomen, angled medially.
Color flow mapping is useful
to identify the uterine artery
as it is seen crossing the
external iliac artery.
• The sample volume- 1 cm
downstream from this
crossover point.

39. • Impedance to flow in the uterine arteries
decreases with gestation.The initial fall (until 24-
26 weeks) is caused by trophoblastic invasion of
the spiral arteries, but continuing fall in
impedance may be explained in part by a
persisting hormonal effect on elasticity of arterial
walls.
• This adaptation is intended to ensure a sustained
increase in blood flow to the uterus during
pregnancy.

40. CHARACTERISTIC UTERINE
ARTERY WAVEFORM
• Non-pregnant and 1st trimester waveform-
steep systolic slope, an early diastolic notch
and small amount of diastolic flow.

41. • >20 weeks AOG-progressively increasing and
extensive diastolic flow
• The presence of notch in the waveform and an
increase in impedance index at > 22 weeks
AOG is abnormal

42. • The failure to establish a low resistance vascular
circuit is the main pathophysiologic rationale for
the Doppler investigation of the uterine artery
• Abnormal Uterine Artery circulation has been
associated with FGR, preeclampsia, preterm
delivery.

43. • Women with increased AFP, inhibin, BHCG, or
decreased free estriol are potential candidates for
Uterine Artery Doppler assessment
• Abnormal analytes + abnormal Uterine artery
Doppler associated with markedly increased risk of
PE, FGR, abruptio placenta and fetal demise.

44. NORMAL WAVEFORM
PARAMETERS
• Qualitatively by the subjective assessment of the flow
velocity waveform (presence or persistence of notch or
presence of small diastolic waveform)
• Quantitatively
SD ratio > 2.6 at 28 weeks AOG
RI = (PSV-EDV) / PSV
normal (low resistance) RI < 0.55
High resistance
bilateral notches RI > 0.55
unilateral notches RI > 0.65
PI = (PSV - EDV) /TAV

45. 30WKS 4DYS

46. Significance of UA notching
• The presence of notching after 22 weeks is indicative of
increased uterine vascular resistance and impaired
uterine circulation
• Uterine artery notching is associated with
Pregnancy induced hypertension (PIH)
placental abruption
intra-uterine growth restriction (IUGR)
increased maternal serum alpha feto protein
(MSAFP)

47. • 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.

48. VENOUS DOPPLER
DUCTUSVENOSUS
• Is a shunt channel.
• Provides connection between the umbilical vein
and inferior vena cava.
• Enabling the oxygenated blood from the umbilical
vein to reach the left atrium via the inferior vena
cava and foramen ovale bypassing the portal vein

49. • A transverse view of the fetal
abdomen-the intrahepatic portion
of the umbilical vein.
• Rotate the probe slightly to image
the entire length of the umbilical
vein to its anastomosis with the
portal sinus.
• Using color flow, the DV is
identified as a small vessel running
from the portal sinus to the junction
of the IVC and the right atrium.
• DV can be identified from the
intrahepatic vessel complex at the
end of the umbilical vein by it high
velocity.

50. Importance:
• screening for aneuploidic anomalies in first
trimester.
• second trimester scanning when there are
concerns regarding
-intrauterine growth restriction (IUGR)
-fetal cardiac compromise
• Pitfall: ductus venosus flow is usually
contaminated by IVC flow.

51. Triphasic pattern in a
normal physiological
situation with forward flow
(i.e. towards the fetal
heart).
This triphasic waveform
comprises:
S wave: corresponds to
fetal ventricular systolic
contraction.
D wave: corresponds to
fetal early ventricular
diastole .
A wave: corresponds to
fetal atrial contraction and
is the lowest point in the
waveform,flow still being in
the forward direction

52. Abnormal waveforms include
• Reduced,Absent,reversal of flow in
ductus venosus A wave
• abnormal indices:
abnormal pulsatility index (PI)
abnormal S wave to A wave ratio (S:A)
abnormal peak velocity index

53. CAUSES OF ABNORMAL DV
WAVEFORM
• Aneuploidy
Down syndrome: around 80% are thought to have abnormal
waveforms
• Congenital cardiac anomalies
congenital pulmonary stenosis
pulmonary atresia
• Fetal arteriovenous malformations leading to shunting
-vein of Galen malformation
• Fetal tumors that lead to arterio-venous shunting
-sacrococcygeal teratoma
• Twin to twin transfusion syndrome: recipient twin
• Maternal diabetes: may exhibit increased PI values

54. • In IUGR fetus,normal venous
Doppler means there is still
adequate compensation to
progressively deteriorating
placental function
• Abnormal venous Doppler is
already a pre-terminal event

55. CLINICAL USE
• 1stTrimester-between 10-14 weeks’ gestation, DV is
used to identify fetuses at increased risk for
chromosomal anomalies
• 2nd and 3rd trimester-growth restricted fetuses with
absent or reversed DV flow during atrial systole have
worse perinatal outcomes. (pending fetal demise
within one week)
• In most IUGR fetuses, sequential deterioration of
venous flow precedes biophysical profile deterioration

56. UMBILICAL VEIN DOPPLER
Characteristics:
• Is monophasic non pulsatile flow pattern with a mean velocity of
~10-15 cm/s.
• Presence of pulsatility-pathological state except:
-early in pregnancy: up to ~13 weeks gestation
-the presence of pulsatility may be higher in chromosomally
abnormal fetuses even in early pregnancy
-when confounded by other movement variables such as
fetal breathing movement
fetal hiccups.

57. • Pulsations in the umbilical
vein in the 2nd and 3rd
trimesters have a high
fetal morbidity and
mortality.
• Pulsations in umbilical
venous flow are known to
be a characteristic sign of
fetal heart failure and
imminent asphyxia.

58. Abnormal umbilical vein doppler

59. INTRAUTERINE GROWTH
RETARDATION
• estimated fetal weight (EFW) is at or below the 10th
percentile for gestational age.
• when fetal biometric parameters fall under the 5th
centile or fall below two standard deviation.

60. An IUGR can be broadly divided into :
• Type I: symmetrical intra-uterine growth
restriction
• Type II: asymmetrical intra-uterine growth
restriction
• Type ӏӏӏ : femur sparing intra-uterine growth
restriction.

61. Causes:
• Maternal conditions
-Maternal malnutrition
-Use of narcotic/alcohol
use/smoking
-maternal diabetes
-maternal vascular
conditions
-placental insufficiency
• Fetal conditions
-multifetal pregnancy
-intra-uterine infections
-chromosomal anomalies

62. USG AND DOPPLER IN
IUGR
• USG findings
-presence of oligohydramnios without ruptured
membranes
-increased head circumference (HC) to abdominal
circumference (AC) ratio (in asymmetrical type)
-decreased total intrauterine volumes
-advanced placental grade

63. Doppler findings
• Umbilical artery Doppler
-increased S/D ratio(s)
-increased resistive index (RI)
• Umbilical venous Doppler
-presence of pulsatility
• Uterine arterial Doppler
-presence of notching in mid to late pregnancy
-increased S/D ratio(s)

64. MULTIFETAL PREGNANCY
• Difference of SD ratios between the twins (between
the 2 cords) should be <0.4 at >28 weeks.
• Doppler velocimetry differentiates small fetuses who
may experience perinatal difficulty(abnormal
waveforms) from genetically small ones (normal
waveforms)
• Doppler velocimetry should be done every 2 weeks
starting from 24 weeks for early signs ofTTTS,
discordancy, and AEDV

65. SUMMARY
• Doppler must be performed in all high risk pregnancy.
• Must not be performed in absolutely normal pregnancy-safety
issues
• Umbilical artery Doppler must be done in suspected placental
insufficiency,should not be used as a screening tool in healthy
pregnancies.
• Umbilical venous pulsations with abnormal umbilical artery
waveforms, needs detailed assessment of fetal health status.
• Measurement of fetal MCA Doppler PSV-predictor of severe
fetal anemia,can be used to avoid unnecessary invasive
procedures in pregnancies complicated with red blood cell
isoimmunization.

66. QUESTIONS

67. Q1.Which among the following is false about
umbilical artery doppler?
A)End diastolic flow is often absent in 1st trimester.
B)UA indices are slightly higher at the fetal
abdominal wall than the placental insertion site.
C)Fetal breathing can affect UA waveforms.
D)Fetal arrhythmia does not affect fetal UA doppler
indices.

68. Q2.Which is true about doppler assessment of
umbilical vein?
A. Pulsation in early gestation upto 13week can be
normally seen.
B. Pulsation can be of single, double or triple type.
C. Pulsation in the 2nd and 3rd trimester
associated with higher morbidity and mortality
even in the setting of normal UA blood flow.
D. All of the above.
ANS:D

69. Q3 Which of the following correctly displays the
ductus venosus normal waveform:
A
.
B
C
Ref: Diagnostic Ultrasound, Rumack et al.
ANS:D

70. Q4 All of the following indicates IUGR; Except:
A. Absent end diastolic volume in Umbilical
Artery
B. Umbilical vein pulsations at 28 weeks of
gestation
C. Reversed flow at ductus venosus A wave
D. Uterine artery notching at 18 weeks POG
ANS:A
Ref: Diagnostic Ultrasound, Rumack et al.

71. Q5. G2P1L1 woman with 29 weeks period of gestation
comes for doppler exam; the presence of which of the
following is predictive of worst fetal outcome
A. Increased MCA PSV
B. Absent EDV in UMA
C. Reversed flow in ductus venosus
D. Non pulsatile Umbilical venous flow
ANS:D

72. Q6.Most commonly used doppler parameter for
assessment of fetal anemia?
A. MCA RI
B. MCA PI
C. MCA S/D ratio
D. MCA PSV
Ref: Diagnostic Ultrasound, Rumack et al.
ANS:C

73. Q7.which is not true about uterine artery notching?
A. Normally seen in the 1st trimester.
B. Should disappear after 22weeks of gestation.
C. B/L notching in late 2nd and 3rd trimester
indicates decreased placental resistance to
uterine flow.
D. In late 2nd and 3rd trimester notching is
associated with pre-eclampsia.
ANS:D
Ref: Diagnostic Ultrasound, Rumack et al.

74. Q8.Match the correct RI values
A) MCA-0.7-0.9, UMA- <0.7, UTA-0.3-0.5
B) MCA-<0.7,UMA -0.7-0.9,UTA-0.3-0.5
C) MCA-0.3-0.5,UMA<0.7,UTA-0.7-0.9
D) MCA-<0.7,UMA-0.7-0.9,UTA-0.3-0.5
ANS:C
Ref: Diagnostic Ultrasound, Rumack et al.

75. Q9:Which of following indicates normal Uterine artery flow
waveform:
ANS:A
D

76. Q10:Which of the following is indicative of IUGR:
A. presence of oligohydramnios
B. increased head circumference (HC) to abdominal
circumference (AC) ratio
C. advanced placental grade
D. All of the above
ANS;D
Ref: Diagnostic Ultrasound, Rumack et al.

77. THANK YOU!!
ANS:D