Fetal biophysical profile

Fetal biophysical profile score (BPS or BPP) refers to the 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 ultrasoundUltrasound

The ultrasound variables are:

• fetal breathing movements: considered abnormal if there is

  • absent breathing 

  • no breathing episode for ≥30 seconds within a 30 minute-minute observation period

• fetal tone: considered abnormal if there is 

  • slow extension with a 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-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 as4/8 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.