The BPP evaluates your baby's movements, heart rate, and the amount of amniotic fluid in the womb. If the score is concerning, you may need further monitoring, or your baby may need to be delivered.
What is a biophysical profile?
A biophysical profile (BPP) is a simple, painless test that's performed during pregnancy to assess your baby's well-being. It combines an ultrasound and fetal heart rate monitoring (a nonstress test).
The test evaluates and scores each of the following:
- Baby's heart rate patterns (also known as a non-stress test)
- Baby's breathing movements. (Babies move their chest muscles and diaphragm in utero to move amniotic fluid in and out of their lungs, just like they will move air in and out of their lungs once they're born.)
- Baby's movements
- Baby's muscle tone (flexing of arms and legs)
- Amount of amniotic fluid
When would I have a biophysical profile?
It can be used in the third trimester of pregnancy for several high-risk pregnancy conditions and also for reassurance about your baby's well-being once you've passed your due date.
Here are some specific reasons you might have a biophysical profile:
- You have preexisting diabetes that's treated with medication, gestational diabetes treated with medication, high blood pressure, or some other medical condition that could affect your pregnancy.
- You have gestational hypertension.
- Your baby appears to be small or not growing properly.
- Your baby is less active than normal.
- You have too much amniotic fluid (polyhydramnios) or too little amniotic fluid (oligohydramnios).
- You're past your due date and your healthcare practitioner wants to make sure your baby is still doing well during his extended stay in the womb.
- You've previously lost a baby in the second half of pregnancy.
- You or your baby has a condition that needs to be monitored.
What's the procedure like?
You may be advised to eat a meal just before the test in the hope that eating will stimulate your baby to move around more. (Although there's no hard evidence that this works, it can't hurt.) It's also a good idea to use the bathroom beforehand, because the test may take up to an hour.
An ultrasound is done to observe your baby's body movements, muscle tone, breathing movements, and to measure the amount of amniotic fluid surrounding her.
Read more about how an ultrasound is done.
Nonstress test (NST)
In this part of the test, your baby's heart rate is monitored for 20 to 30 minutes to see the patterns it makes over time. Certain patterns are reassuring ("reactive") and others are concerning. Sometimes an NST just doesn't give doctors the information they're looking for ("nonreactive").
Learn more about how the nonstress test is done.
What do the results of the BPP mean?
Each of the five components – body movements, muscle tone, breathing movements, amniotic fluid, and heartbeat – is assigned a score of either 0 (abnormal) or 2 (normal). These are added up for a total score ranging from 0 to 10.
- A score of 8 or 10 is "reassuring," or normal.
- A score of 6 is considered "equivocal," or borderline. In this case, you doctor may recommend another BPP in the next day or two, additional monitoring, or that your baby be delivered.
- A score of 4 or less in "nonreassuring" or abnormal. Your doctor may send you to the hospital for closer observation and further testing. If she thinks your baby isn't doing well and needs to be delivered, you'll be induced or have a c-section.
- If the amount of amniotic fluid scores a 0, it means that the deepest pocket of fluid is less than 2 cm or the total fluid is less than 5 cm. (The fluid is measured either in four areas or the deepest pocket.) In this case, your baby will need more testing and/or you may need to deliver right away (particularly if you're near 37 weeks) – even if the other things they looked at seemed fine. Low amniotic fluid means there might be a problem with blood flow in the placenta, and your baby might be having trouble getting enough oxygen.
What is a modified biophysical profile?
A modified BPP is a combination of a nonstress test (fetal heart rate monitoring) and an ultrasound just to measure amniotic fluid. It's a quicker test than a full BPP, and it's considered as reliable.
If the results of the modified profile are not reassuring, more tests, such as a full BPP or a longer continuous fetal monitoring, may be done to follow up. In making a decision about the next step, your doctor will take into account your baby's gestational age, the reasons why the testing is being done in the first place, and which part of the modified BPP is concerning.
Wondering what other tests you might have in your third trimester? This rundown of prenatal tests will give you a good overview.