If a pregnancy is deemed high-risk, extra checks on a baby-to-be might be in order. One of these is the biophysical profile (BPP), an ultrasound test that sometimes includes fetal heart rate monitoring.

BPPs are short and simple to conduct, typically taking around 30 minutes. You’ll undergo an ultrasound to track how your baby is breathing and moving, what her muscle tone is like and how much amniotic fluid is in the womb.

The technician may also add on more comprehensive screening with fetal heart rate monitoring, called a nonstress test, to evaluate your baby’s condition through characteristics in the fetal heartbeat.[1]

Here’s a closer look at why BPP tests are sometimes performed, when you might get one (or a similar test known as a modified biophysical profile), and how to make sense of the results. 

What is a biophysical profile (BPP)?

The biophysical profile (BPP) is an assessment of fetal well-being that can be done on its own or when other tests (like the nonstress test) require follow-up.

For instance, it might be performed if a doctor or midwife is concerned that a baby isn’t moving around normally or if amniotic fluid levels in the womb are getting too low.

When all the measurements come back normal, it is an excellent test to reassure you and your provider that your baby is doing just fine. However, sometimes, further testing may be needed to provide a more accurate picture of your baby's condition.[2]

Who is a biophysical profile for?

The doctor may order a biophysical profile if they suspect that mother and baby are at a higher risk of certain complications. The test can tell a mother’s care team if the placenta and baby are healthy and it is safe to continue the pregnancy or if it's time to deliver.

BPPs most commonly take place in the third trimester, usually after 32 weeks, but they can be conducted any time after 24 weeks. They’re typically used for moms who:

  • Are carrying twins or multiples
  • Have conditions that raise the risk of complications, such as high blood pressure or diabetes
  • Have a pregnancy affected by fetal growth restriction
  • Are past their due date 
  • Are experiencing reduced fetal movement 
  • Have too much or too little amniotic fluid
  • Have Rh sensitization  

How a biophysical profile (BPP) is done

A BPP is an ultrasound exam that looks at four specific variables over a period of thirty minutes. But rather than looking at organs and size measurements, the test evaluates four aspects of life in utero:[3]

  • Fetal breathing: Visualization of the baby's chest moving as she takes practice breaths
  • Fetal movement: Movements of the body or limbs
  • Fetal tone: Flexion and extension of an arm or leg
  • Volume of amniotic fluid: The amount of amniotic fluid surrounding your baby

What do BPP test results mean?

BPP test results reflect a number of different markers, like your baby’s heart rate, breathing (which includes hiccups), movement and muscle tone, as well as amniotic fluid levels.

Your sonographer will assign a BPP score of 0 or 2 points in each of the four categories listed above and then tally them up. Here’s what BPP score totals mean:

  • A score of 8 to 10 is reassuring and represents a normal, well oxygenated fetus; no need for intervention, continued weekly testing can be recommended.
  • A score of 4 to 6 may require a second BPP within 24 hours, more immediate further testing or, depending on how far along you are in your pregnancy, your baby may be delivered.
  • A score of 0 or 2 would almost always lead to immediate delivery.

Keep in mind that even if the biophysical profile score is considered "normal," low amniotic fluid levels mean that more monitoring needs to be done and, in some cases, delivery may be necessary.

Risks of a biophysical profile

Biophysical profiles are noninvasive, so undergoing one doesn’t pose any risks to you or your baby. But having the test can understandably make you feel worried or stressed. Some limited evidence suggests that extreme anxiety could potentially affect the results of the nonstress test portion of the BPP. 

If the thought of a biophysical profile seems overwhelming, chat with your practitioner. You can talk through your concerns together, which can help put your mind at ease. And the test itself is a chance to get a look at your baby, so that is always fun!

The modified biophysical profile

A modified biophysical profile is another type of prenatal test. It combines the nonstress test with an ultrasound to measure your amniotic fluid levels. 

A modified biophysical profile is less involved but can be just as useful as a full BPP. Low levels of amniotic fluid may indicate that the baby isn't producing enough urine, and that can mean there is an issue with the placenta.

If your baby reacts appropriately to the nonstress test and your amniotic fluid levels are sufficient, all is likely well.

Being told you need a biophysical profile can be worrying. Just remember that the test doesn’t always mean something is seriously wrong. More importantly, the findings will help protect your baby (and you!) to ensure the healthiest possible pregnancy and the smoothest possible delivery.