dr. farzad afzali,pregnancy doppler

8/13/2019 Dr. Farzad Afzali,Pregnancy Doppler

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Presented by:

Dr. Farzad AfzaliKasra medical imaging center


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An early stage in fetal adaptation to

hypoxemia

increased blood flow in DV to protect the brain,heart, and adrenals

central redistribution of blood flow

( brain-sparing reflex)

reduced flow to the peripheral and placentalcirculations


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Under physiologic conditions, 60 to 70

percent of umbilical venous blood in the

human fetus is distributed to the liver and the

remainder to the heart.

With chronic hypoxemia, this proportion may

be modulated so that a larger proportion of

umbilical venous blood can bypass the liver to

reach the heart


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The middle cerebral artery (MCA) in the fetal brain

Normally high-impedance

Most accessible to U/S imaging

More than 80% of cerebral blood


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Average of both MCAs must be calculated for more

precise result.

Compression of the fetal head causes increasing arterial

resistance.( false negative of IUGR)


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The best predictor for fetal acidemia

is PI of thoracic aorta.

The best predictor of fetal hypoxia is

PI of MCA.


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The damage that obliterate small muscular arteries in

placental tertiary stem villi

absent flow or even reversed flow, suggestive more

than 70% damage of placenta.

commonly associated with severe IUGR and

oligohydramnios

Waveforms obtained from the placental end of cord

show more end-diastolic flow, thus lower RI & PI,than waveforms obtained from the abdominal cord

insertion. (No significance on clinical practice)


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Velocimetry of uterine artey should be obtained

after the vessel crosses the hypo gastric artery and

vein, at the uterus-cervical junction, before it

divides to cervical and uterine branches.

The best predictor of PIH is notch in the uterine

artery & RI>61.5 % after 22 w of gestation.


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Venous indices reflect : ventricular function

Fetal hypoxia

Myocardial lactic acidosis


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DV a wave decrease

Reverse EDF UA -- Reverse a wave DV

Pulsatile UV

Constriction of cerebral circulation

Death within 96 hours


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At the level of AC measuring, ductus venosus canbe identified as it branches from hepatic vein.

It has high speed flow with biphasic waveform.

The first phase corresponding ventricular systole,the second phase to early diastole and nadir to theatrial kick.


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Umbilical vein displays pulsatility in first trimester

but this disappears with advancing gestation in the

pregnancy unaffected by FGR
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1530021&dopt=Abstracthttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1530021&dopt=Abstract


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In clinical practice, it is necessary to carry out serial

Doppler investigations to estimate the duration of

fetal blood flow redistribution.

The onset of abnormal venous Doppler resultsindicates deterioration in the fetal condition and

iatrogenic delivery should be considered


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Preterm growth restricted fetuses with elevated

umbilical artery Doppler resistance have an overall

perinatal mortality rate of 5 6percent .This rate increases to 5percent when end-diastolic

velocity is absent.

and rises to 38 8percent when venous Doppler indicesbecome abnormal (predominantly due to an increase in

the rate of stillbirth).


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dr. farzad afzali,pregnancy doppler

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