| THE BIOPHYSICAL PROFILE SCORE
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 are abolished (Vintzileos, 1987). The cumulative effect
of repetitive hypoxemia is progressive oligohydramnios and fetal growth
restriction. Hence, the presence of oligohydramnios with all of the other
variables of the biophysical profile being normal may reflectchronic uteroplacental
insufficiency.
There is a delay
in central nervous system development with growth restriction. Hence, the
distribution of fetal breathing movements, fetal movements and fetal eye
movements (an assessor of fetal state) are different than in control fetuses.
These differences are particularly striking when there is an absence of
diastolic flow in the umbilical artery (Rizzo 1987).
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Table I. Components of the 30 minute Biophysical Profile
Score
|
| 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 |
| Fetal
breathing movements |
>1
episode of >30 seconds in 30 minutes
- Hiccups are considered
breathing activity.
|
| Amniotic fluid volume |
A
single 2 cm x 2 cm pocket is considered adequate. |
| Non-stress
test |
2 accelerations
> 15 beats per minute of at least 15 seconds
duration. |
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Table II. Distribution of Biophysical Profile
Scores
|
| Score |
Description |
Percent |
| 8 -
10 |
Normal |
97.52 |
| 6 |
Equivocal
|
1.72 |
| 4 |
Abnormal |
0.52 |
| 2 |
Abnormal |
0.18 |
| 0 |
Abnormal |
0.06 |
|
Derived from: Manning FA et al. Am J Obstet Gyncol
1985;151:343.
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Table III. Perinatal Mortality and the Biophysical Profile
Score
|
| Score |
Perinatal
Mortality/1000 |
| 8 -
10 |
1.86* |
| 6 |
9.76 |
| 4 |
26.3 |
| 2 |
94.0 |
| 0 |
285.7 |
| |
*0.8/1000 for
structurally normal fetuses with a normal test within 7 days |
|
Derived
from:
Manning FA et al. Am J Obstet Gynecol 1990;162:703.
Manning FA et al.
Am J Obstet Gynecol 1985;151:343.
Manning FA (ed): Fetal Assessment:
Principles and Practices. Norwalk CT, Appleton and Lange 1995, p 221.
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Table IV. Maternal and Fetal Causes of Stillbirth within one week of
a normal Biophysical Profile Score
|
| Maternal |
Placental
abruption
Diabetic ketoacidosis
Sickle cell crisis
Drug
overdose
Motor vehicle accident
Acute myocardial infarction
Acute
alcohol poisoning |
| Fetal |
Fetomaternal
hemorrhage
Cord prolapse
Ruptured membranes
Vase previa
Cord
entanglement
Umbilical artery thrombosis |
| Derived
from: Dayal AK et al. Am J Obstet Gynecol 1995;
181:1231-1236. |
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| Result |
Interpretation |
Risk
of Asphyxia*
(%) |
Risk of Fetal
Death (per
1000/wk) |
Recommended Treatment |
| 10/10 |
Nonasphyxiated |
0 |
0.565 |
Conservative |
| 8/10 (normal AFV) |
Nonasphyxiated |
0 |
0.565 |
Conservative |
| 8/8 (NST not performed) |
Nonasphyxiated |
0 |
0.565 |
Conservative |
| 8/10 (decreased AFV) |
Chronic compensated
asphyxia |
5-10 (estimate) |
20-30 |
If mature (>37 wk), deliver
If immature, serial testing
(twice weekly) |
| 6/10 (normal AFV) |
Acute asphyxia
possible |
0 |
50 |
If mature (>37 wk), deliver
If immature, repeat test in 24 h
and if <6/10, deliver |
| 6/10 (decreased AFV) |
Chronic asphyxia with
possible acute |
>10 |
>50 |
Factor in gestational age
If >32 wk, deliver
If <32 wk,
test daily |
| 4/10 (normal AFV) |
Acute asphyxia likely |
36 |
115 |
Factor in gestational age
If >32 weeks, deliver
If
<32 wk, test daily |
| 4/10 (decreased AFV) |
Chronic asphyxia with
acute
asphyxia
likely
|
>36 |
>115 |
If >26 wk, deliver |
| 2/10 (normal AFV) |
Acute asphyxia almost
certain |
73 |
220 |
If >26 wk, deliver |
| 0/10 |
Gross severe asphyxia |
100 |
100 |
If >26 wk,
deliver |
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| *Umbilical venous blood pH less than 7.25 |
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