Biophysical Profile

What is a biophysical profile?

A biophysical profile (BPS or BPP) is a test typically performed after 32 weeks of pregnancy to evaluate the fetus’s health. It’s often done when your pregnancy is high risk due to health conditions or you have irregular test results. It helps answer questions your healthcare provider has about your fetus’s well-being.

Pregnancy care providers perform a biophysical profile with an ultrasound. It looks at four different areas to come up with a score. A biophysical profile is noninvasive and low risk.

It uses a scoring system to rate the fetus in these areas:

• Body movement: The fetus moves its limbs or body.
• Muscle tone: The fetus opens and closes its hands or bends and extends its arms or legs.
• Breathing movements: The fetus has continuous, rhythmic breathing.
• Amniotic fluid volume: There’s a pocket of amniotic fluid that measures at least 1 centimeter (cm) across and 2 centimeters vertically.

There are times that a nonstress test (NST) is needed if one or more of the areas aren’t met. This test looks for accelerations in the fetus’s heart rate.

Your provider may perform a modified biophysical profile instead of the complete biophysical profile. The modified biophysical profile combines a nonstress test (measuring heart rate) with an ultrasound assessment of the amount of amniotic fluid.

What is the purpose of a biophysical profile?

Your pregnancy care provider may order a biophysical profile if your pregnancy is high risk or goes beyond 40 weeks. They may also suggest a biophysical profile if you have any of the following conditions:

• Hypertension, lupus, renal disease or thrombocytopenia.
• There’s a decrease in the fetus’s movements.
• Previous stillbirth or other negative pregnancy outcomes.
• Expecting multiples (twins or triplets).
• Pregnancy-related hypertension (high blood pressure) or preeclampsia.
• Possible intrauterine growth restriction. (The fetus is measuring smaller than average.)
• Diabetes before pregnancy or diabetes associated with pregnancy (gestational diabetes).
• Too much or too little amniotic fluid.
• You’re Rh negative.
• You’re 35 or older at the time of delivery.
• You have obesity (a body mass index, or BMI, of 30 or higher).

What are the five parameters of a biophysical profile?

There are five parts to a biophysical profile. The first is a nonstress test, which assesses the fetus’s heart rate in response to its movement or contractions.

The other four parts are assessed by ultrasound. They include looking at:

• The fetus’s breathing movements.
• The fetus’s body movements.
• The fetus’s muscular tone, such as flexing and extending limbs.
• The amount of amniotic fluid. Amniotic fluid is a water-like substance that surrounds the fetus in your uterus

How is the biophysical profile performed?

Your provider may perform the following as part of a biophysical profile:

• Ultrasound examination: During an ultrasound, you’re lying down or reclining on an exam table. Your provider moves a device called a transducer (or probe) over your abdomen to produce sound waves. The transducer converts the sound waves to images that can be viewed on a screen.
• Nonstress test: An electronic fetal monitor measures the fetus’s heart rate while you’re reclining or laying down on an exam table. Your provider places a belt with an electronic sensor around your abdomen. Then, the sensor measures and records the fetal heart rate. The test usually takes about 20 minutes, but can go on for 40 minutes depending on fetal activity. There should be two or more accelerations in their heart rate. If there are fewer than two, it may indicate the fetus is asleep. In that case, your provider may use a buzzer or a loud noise to stimulate movement. In some cases, your provider will place a second monitor with a sensor around your abdomen. This monitor measures and records your uterine contractions.

How long does a biophysical profile take?

You can expect a biophysical profile to take no longer than 30 to 40 minutes.

What are the risks of a biophysical profile?

Biophysical profiles are noninvasive tests and completely painless. There are no risks to you or the fetus. Be sure to discuss any concerns you have with your healthcare provider before the test.

How does scoring work for a biophysical profile?

Each of the four components receives either zero or two points. You can’t get one point. The maximum you can score is eight points. The higher your score, the better health the fetus is assumed to be in.

The criteria to earn two points for each component are:

• Fetal gross body movement: Three or more separate movements of the fetus’s body or limbs in 30 minutes.
• Fetal muscle tone: One or more episodes of active extension and flexion of an arm or leg, or the opening and closing of a hand, in 30 minutes.
• Fetal breathing movements: At least one episode of continuous breathing that lasts at least 30 seconds during the 30-minute test.
• Amniotic fluid volume: At least one pocket of amniotic fluid that measures 1 centimeter across and 2 centimeters vertically.

Any component that doesn’t meet the criteria above is considered irregular and receives a score of zero points.

Don’t panic if the results of your biophysical profile are abnormal. It doesn’t mean there’s a problem. Certain conditions and factors could affect your score. This is when your provider may order a nonstress test. In a nonstress test, there need to be at least two episodes of heart rate acceleration in 20 minutes. This means when the fetus moves, its heartbeat should increase. This is similar to how your heartbeat increases when you walk up the stairs. If two accelerations occur, you get an additional two points.

How long does it take to get your results?

You typically have results on the same day. Your healthcare provider will try to schedule an appointment with your obstetrician shortly after finishing the test. Your obstetrician will explain the results to you at that time.

What is a good biophysical profile score?

Your biophysical profile score total means:

• A score of eight points with good amniotic fluid volume is regarded as “reassuring,” which means normal.
• A score of six indicates that there may be problems and additional testing is needed. This could mean repeating the test in 12 to 24 hours or considering an early delivery.
• If you score four or less, your healthcare provider may need to deliver your baby right away. In some cases, further testing is needed and delivery can be delayed until absolutely necessary.

Closer monitoring is always needed if your amniotic fluid level is too low, even if your other scores are normal.

What are the advantages and disadvantages of a biophysical profile?

The advantages of the biophysical profile include:

• There’s little risk to you or the fetus.

The drawbacks include:

• It’s not as reliable when it’s performed before 32 weeks of pregnancy.
• The results may be affected by corticosteroids. The fetus’s breathing may falsely increase and its movement may decrease for several days after you’re treated with corticosteroids.
• The test may need to be repeated.

A note from Cleveland Clinic

It’s normal to feel anxious or nervous about tests during pregnancy. A biophysical profile is a safe test that poses no risks to you or the fetus. It allows your pregnancy care team to assess the fetus’s health and determine if delivery is necessary. In most cases, everything is fine, and the test is done as a precaution. Share any concerns you have about the test with your healthcare provider. They can help reassure you that the fetus will be OK.