A biophysical profile (BPP) is a test that combines a nonstress test with ultrasound to check the health of the fetus. A nonstress test (NST) measures the fetal heart rate in response to the movements of the fetus. An ultrasound is a diagnostic technique that uses high-frequency sound waves to create an image of the fetus. Biophysical profile testing is usually performed in the last trimester of pregnancy.
There are five parts to a biophysical profile:
- the nonstress test
Plus four areas assessed by ultrasound:
- fetal breathing movements
- fetal movements
- fetal tone
- amniotic fluid volume
How is a biophysical profile performed?
Each of the five areas of the biophysical profile has a possible total score of two points, for a total of 10 points. A score of:
- eight to 10 is usually considered normal
- six is considered equivocal (uncertain)
- four or less is considered abnormal
If the score is questionable or abnormal, or if the amniotic fluid volume is too low, additional testing may be needed.
What is a modified biophysical profile?
Another type of BPP, called a modified BPP, is sometimes performed. The modified BPP combines the nonstress test and an evaluation of the amount of amniotic fluid, called the amniotic fluid index (AFI). The largest pocket of amniotic fluid is measured in each of the four quadrants of the mother's abdomen using ultrasound. All four quadrants added together give the amniotic fluid index.