Transcript Fetal Biophysical Profile in high risk pregnancy Presented by:

Fetal Biophysical Profile
in
high risk pregnancy
Presented by:
Dr. S. Rouholamin
 Hypoxia : Low Oxygen tension
 Asphyxia : Low Oxygen and high CO2
 Ischemia : Drop in blood flow
 Prediction of the effect of an asphyxial
insult on the fetus requires a measure of :
Severity of the asphyxia.
Duration of the asphyxia.
 18-48 hrs(Neuronal necrosis)
48-72hrs(apper. of white matter macroph.
&Astrocy.).
>4days cavitation visible on head U/S
comment
 Fetal asphyxia may or may not be concomitant
with clinical presentation. (based on severity
,duration & location of insult)
Component
Definition
Fetal movements
3 body or limb movements
Fetal tone
One episode of active extension and
flexion of the limbs; opening and
closing of hand
episode of >= 30 seconds in 30
minutes Hiccups are considered
breathing activity.
single 2 cm x 2 cm pocket is considered
adequate.
Fetal breathing
movement
Amniotic fluid volume
Non-stress test
2 accelerations > 15 beats per minute
of at least 15 seconds duration.
 Fetal movement and fetal tone develop
between 7.5 and 9 weeks’ menstrual age
 Fetal breathing movements are
detectable by, at least 17-18 weeks’
gestation
The biophysical profile score is
continued for a maximum of 30 minutes
Oligohydramnios is now defined as a
pocket of amniotic fluid < 2.0 x 2.0 cm
(Manning, 1995A)
The Biophysical Profile (BPP)
•Between 24 and 28 weeks' gestation, approximately
50 percent of NSTs are nonreactive.
•In contrast sonographically evaluated variables are
valid early in gestation and account for three of the
five components of the biophysical profile.
•The biophysical profile may be used to verify fetal
well being when the nonstress test is not reactive.
The Biophysical Profile (BPP)
•Fetal movement and fetal tone develop
between 7.5 and 9 weeks’ menstrual age.
•Fetal breathing movements are detectable by,
at least 17-18 weeks’ gestation.
•Amniotic fluid may be reduced as early as
17.5 weeks by fetal acidosis.
•The components of the biophysical profile
develop sequentially. In order of appearance:
tone, movement, breathing, reactivity.
The Biophysical Profile (BPP)
•Fetal state (wake-sleep cycle) plays an
important role in the interpretation of the
biophysical profile score.
•In quiet sleep the average time to obtain a
normal biophysical profile score is 26.3 minutes.
•The biophysical profile score is, therefore,
continued for a maximum of 30 minutes.
The Biophysical Profile (BPP)
•The sonographic variables that develop last
in gestation are the most sensitive to
acidosis and would be the first components
of the BPP to become abnormal.
•The NST, breathing, and amniotic fluid
volume are the most significant variables.
The Biophysical Profile (BPP)
•The non-stress test and fetal breathing
movements are suppressed when the pH
falls below 7.2.
•If the fetal pH falls below 7.10 fetal tone
and fetal movements become abolished
•The presence of oligohydramnios with all of
the other variables of the biophysical profile
being normal may reflect chronic
uteroplacental insufficiency
Components of the Biophysical Profile Score
Component
Definition
Non-stress test
Two or more fetal heart rate accelerations peak (but do not
necessarily remain) at least 15 beats per minute above the
baseline and last 15 seconds from baseline to baseline within
a 20-minute period with or without fetal movement discernible
by the woman.
Amniotic fluid
volume
A single 2 cm x 2 cm pocket is considered adequate or AFI
greater than 5.0 cm .
Fetal breathing
movements
One or more episodes of rhythmic fetal breathing movements
of 30 seconds or more within 30 minutes.
Hiccups are considered breathing activity.
Fetal movements
At least three discrete body or limb movements.
Episodes of continuous movement are considered as a single
movement.
Fetal tone
One or more episodes of extension of a fetal extremity or
trunk with return to flexion, or opening or closing of a hand
Perinatal Mortality and the Biophysical Profile Score
Score
Interpretation
Perinatal Mortality/1000
8- 10
Normal
1.86*
6
Equivocal
9.76
4
Abnormal
26.3
2
Abnormal
94.0
0
Abnormal
285.7
*The perinatal mortality is 0.8/1000 for structurally normal fetuses with a normal test
within 7 days.
Maternal and Fetal Causes of Stillbirth within One Week
of a Normal Biophysical Profile Score
Maternal
Fetal
Placental abruption
Fetomaternal hemorrhage
Diabetic ketoacidosis
Cord prolapse
Sickle cell crisis
Ruptured membranes
Drug overdose
Vase previa
Motor vehicle accident
Cord entanglement
Acute myocardial infarction
Umbilical artery
Acute alcohol poisoning
thrombosis
Factors Affecting the Biophysical Profile
Interpretation of an Equivocal or Abnormal BPP
The absence of a biophysical variable may
reflect:
•Normal fetal activity and sleep cycles
•An inability of the central nervous system to
perform that function
•Hypoxia
•External influences
•Fetal breathing movements may be
•Stimulated by caffeine and hyperglycemia.
•Inhibited by hypoglycemia, maternal supine
hypotension, cigarette smoking, alcohol,
diazepam and meperidine.
Action for Equivocal or Abnormal BPP
• The term fetus is generally delivered for a score of 6.
• However, a score of 6 in a preterm fetus is usually
repeated in 12 to 24 hours. In the interim, antenatal
steroids may be given for pregnancies of less than
34 weeks of gestation.
• Delivery is usually indicated for BPP score of 4 or
less.
• Oligohydramnios always requires further evaluation.
Patients with a biophysical profile score of 6 or less
should be considered for transfer to Labor and
Delivery for further observation or delivery and
physician notified.
Special Considerations
Rupture of the membranes does not alter the shortterm sonographic variables of the biophysical profile
in the healthy fetus.
The
negative predictive value of a normal
biophysical profile score is not as high with an
anomalous fetus, in contrast to a structurally normal
fetus.
Sudden fetal deaths have been reported following a
normal biophysical profile score in fetuses with
gastroschisis, omphalocele, and diaphragmatic
hernia.
Special Considerations
The observation of an abnormal biophysical
profile in an anomalous fetus does not correlate
very well with the presence of hypoxia.
The biophysical profile score cannot be used
in fetuses with congenital muscular diseases or
central nervous system conditions that would
affect muscular function.
If an anomalous fetus had a previously
normal biophysical profile score, a decreasing
score should be considered an indication of
compromise
Fetal breathing movements. Video shows a rhythmic
deflection of the fetal chest wall and diaphragm that is clearly
distinct from the rhythmic motion of the fetal heart. Note that
the image begins in the transverse view, but the ultrasound
transducer is then rotated to show a sagittal view and, finally,
an oblique view. The episode of continuous fetal breathing
lasts well in excess of the required 20-second period.
False fetal breathing movements. Although some transient
fetal breathing movements are seen, the video does not
include 20 seconds of continuous fetal breathing. Note that
the maternal breathing and aortic pulse seen posteriorly and
the fetal aortic pulse seen on the sagittal view, along with
fetal cardiac activity, can cause deflections of the fetal chest
wall, which can be mistaken for fetal breathing movements.
Gross fetal movements and tone. Video
demonstrates generalized movements of the
fetal lower extremities, including 1 episode of
flexion and extension.
Gross fetal movements and tone. Video demonstrates
generalized movements of the fetal upper extremities.
The upper extremity rests in front of the fetal chest and
chin. Although the ultrasound transducer is moving
laterally across the maternal abdomen, 2 distinct
episodes of flexion and extension are seen. Note the
many cross-sectional views of the 3-vessel umbilical
cord and the floating echogenic particles of vernix in the
amniotic fluid.
Amniotic fluid index. The largest pocket of fluid
is measured in each quadrant of the maternal
abdomen in the vertical dimension. Then, each
value is added to yield the amniotic fluid index.