Fetal biophysical profile

Last revised by Michael Fielden McNeeley on 2 Jul 2022

Fetal biophysical profile score (BPS or BPP) refers to assessment of four discrete biophysical variables by ultrasound. It is a standard tool in antepartum fetal assessment. It is usually assessed after 28 weeks of gestation.

Radiographic features

Antenatal ultrasound

The ultrasound variables are:

  • fetal breathing: considered abnormal if there is
    • absent breathing 
    • no breathing episode for ≥30 seconds within a 30 minute observation period
  • fetal tone: considered abnormal if there is 
    • slow extension with return to partial flexion
    • absent fetal movement
  • fetal movement (gross body movement): considered abnormal if there is 
    • <2 episodes of body/limb movements within a 30 minute lapse
  • amniotic fluid volume: considered abnormal if the largest pocket is <2 x 2 cm

Each of these parameters is given a score of either 0 or 2 points, where an abnormal score gets 0 while a normal score gets 2.

Therefore on ultrasound assessment, a total score is given out of 8. An overall abnormal score out of 8 is often taken as 4/8 or less.

A continuous observation for at least 30 minutes is must, before defining any variable as “absent”, due to fetal sleep wake cycles 7.

In addition to this, an additional non sonographic variable (non-stress test) with two extra points can also be taken into account. In which case a score is given out of 10.

Potential confounding variables

Some reports show maternal fasting resulting in reduced fetal breathing movements which can in turn affect the BPP score 5

Additional work up

Umbilical arterial Doppler assessment is usually additionally carried out to evaluate fetuses with abnormal BPP scores.

History and etymology

The score was initially proposed by F A Manning et al. in 1980 3.

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