Biophysical profile


A biophysical profile is a prenatal ultrasound evaluation of fetal well-being involving a scoring system, with the score being termed Manning's score. It is often done when a non-stress test is non reactive, or for other obstetrical indications.
The "modified biophysical profile" consists of the NST and amniotic fluid index only.

Procedure

The BPP has 5 components: 4 ultrasound assessments and an NST. The NST evaluates fetal heart rate and response to fetal movement. The five discrete biophysical variables:
  1. Fetal heart rate
  2. Fetal breathing
  3. Fetal movement
  4. Fetal tone
  5. Amniotic fluid volume
ParameterNormal Abnormal
NST/Reactive FHRAt least two accelerations in 20 minutesLess than two accelerations to satisfy the test in 20 minutes
US: Fetal breathing movementsAt least one episode of > 30s or >20s in 30 minutesNone or less than 30s or 20s
US: Fetal activity / gross body movementsAt least three or two movements of the torso or limbsLess than three or two movements
US: Fetal muscle toneAt least one episode of active bending and straightening of the limb or trunkNo movements or movements slow and incomplete
US: Qualitative AFV/AFIAt least one vertical pocket > 2 cm in the vertical axis or AFI of 5 cmLargest vertical pocket

Use of vibroacoustic stimulation to accelerate evaluation has been described.

Interpretation

Each assessment is graded either 0 or 2 points, and then added up to yield a number between 0 and 10. A BPP of 8 or 10 is generally considered reassuring. A BPP normally is not performed before the second half of a pregnancy, since fetal movements do not occur in the first half.
The presence of these biophysical variables implies absence of significant central nervous system hypoxemia/acidemia at the time of testing. By comparison, a compromised fetus typically exhibits loss of accelerations of the fetal heart rate, decreased body movement and breathing, hypotonia, and, less acutely, decreased amniotic fluid volume.
BPPRecommended management
≤2
4
  • Labor induction if gestational age >32 weeks
  • Repeating test same day if <32 weeks, then delivery if BPP <6
    • 6
  • Labor induction if >36 weeks if favorable cervix and normal AFI
  • Repeating test in 24 hours if <36 weeks and cervix unfavorable; then delivery if BPP <6, and follow-up if >6
    • ≥ 8
  • Labor induction if presence of oligohydramnios