Transcript Biophysical Profile& Color Doppler ultrasound in the high risk

Presented by:
Dr. Farzad Afzali
Kasra medical imaging center

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 ( brainsparing reflex)
• reduced flow to the peripheral and placental
circulations
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
◦ Middle cerebral artery
◦ Aorta
◦ Umbilical artery
◦ Uterine artery
◦ IVC
◦ Ductus venosus

The middle cerebral artery (MCA) in the fetal brain
• Normally high-impedance
• Most accessible to U/S imaging
• More than 80% of cerebral blood
Average of both MCAs must be calculated for more
precise result.
Compression of the fetal head causes increasing arterial
resistance.( false negative of IUGR)
 The best predictor for fetal acidemia
is PI of thoracic aorta.
 The best predictor of fetal hypoxia is
PI of MCA.
• 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)
◦ 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.

Venous indices reflect :
• ventricular function
• Fetal hypoxia
• Myocardial lactic acidosis
•
Decrease cardiac output secondary to
myocardial dysfunction
• Rise in CVP
• Increase in reverse flow in atrial systole
• Transmitted down venous system - the further from
the heart the greater degree of cardiac dysfunction
• DV ‘a’ wave decrease
• Reverse EDF UA -- Reverse ‘a’ wave DV
• Pulsatile UV
• Constriction of cerebral circulation
• Death within 96 hours
◦ At the level of AC measuring, ductus venosus can
be 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 the
atrial kick.
◦ Umbilical vein displays pulsatility in first trimester
but this disappears with advancing gestation in the
pregnancy unaffected by FGR
◦ 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 results
indicates deterioration in the fetal condition and
iatrogenic delivery should be considered
• PI of MCA/PI of TA must be more than 0.9 before 30,less
than 0.8 before the 34 & less than 0.75 before the 36 weeks
of pregnancy.
• PI of MCA/ PI of UA must be >1.08 during pregnancy.
• The larger values are abnormal & termination may be
considered after 35-37 weeks of pregnancy.
Preterm growth restricted fetuses with elevated
umbilical artery Doppler resistance have an overall
perinatal mortality rate of 5.6 percent .
This rate increases to 11.5 percent when end-diastolic
velocity is absent.
and rises to 38.8 percent when venous Doppler indices
become abnormal (predominantly due to an increase in
the rate of stillbirth).
• Reverse flow in the umbilical artery, along with
pathologic waveform in the venous system are the
best
predictor
of
sever
fetal
distress,
so
termination of pregnancy must be considered as
soon as possible.