Biophysical Profile – Components & Interpretation

A biophysical profile is one of the antepartum fetal surveillance tools done by ultrasound which is used by your doctor to assess if there is uteroplacental insufficiency.

Why it is Done?

If your pregnancy is high risk like for example if you have either one of these conditions

  • high or low amniotic fluid volume (oligo or polyhydramnios)
  • previous history of fetal death
  • multiple pregnancy plus complication
  • if your date passes by more than 2 weeks (above 42 weeks. It is called post-term pregnancy)
  • if you diagnosis with preeclampsia or other vascular diseases

if you have a high-risk pregnancy, your doctor needs to do a biophysical profile to make sure the baby is okey.

How it is Done?

The biophysical profile contains 5 components. And 4 of them assessed by ultrasound and can take up to 30 minutes maximum. The other test (non stress test) is to hear the fetal heartbeat during fetal movement. You need to lie to the left lateral position for 40 minutes maximum. Otherwise, it doesn’t need any pre-procedure preparation.

Does the Biophysical Profile Test have a Risk to the Baby?

Biophysical profile has no risk for you and your baby.

Components of Biophysical Profile

It has 5 main components each graded either 0 or 2. (no such grade as 1 )

  • Fetal tone
  • Fetal movement
  • Breathing movement
  • Nonstress test
  • Amniotic fluid volume

Let’s see each one by one.

Fetal Tone

Your doctor starts to detect a fetal tone starting from the gestational age of 7. It is the first variable to appear compared to the others. Amazingly, it is the last variable to disappear in case of uteroplacental insufficiency.

Grade 2 fetal tone defined as

At least one episode of fetal extremity extension and subsequent flexion.

Grade 0 fetal tone defined as

Partial or no flexion and extension of fetal extremity.

Fetal Movement

The fetal movement saw in the 9th week of gestational age.

Grade 2 fetal movement defined as

Atleast 3 discrete body or limb movement of the fetus within 30 minute

Grade 0 fetal movement defined as

Less than 3 fetal movement

Fetal Breathing Movement (FBM)

FBM was first detected by ultrasound at the gestational age of 20 weeks.

Grade 2 FBM defined as

At least one episode of breathing lasting 30 seconds within 30 minute

Grade 0 FBM defined as

No breathing movement was detected or breathing which lasts less than 30 seconds.

Nonstress Test (NST)

It is a short term indicator of fetal acid-base status. Normally when there are fetal movements, fetal heart rate increases. It is cheap, simple, and has no direct maternal and fetal risk. But it has a high false-positive rate.

Reactive NST test (Graded as 2 points)

At least 2 fetal heart rate acceleration (increase by 15 beats above the baseline) lasting at least 15 minutes within 20 minutes of the beginning of the test.

Nonreactive NST test (Graded as 0)

If the above criteria are not met over 40 minutes, we call it a nonreactive test. And it graded as 0.

Amniotic Fluid Volume

Unlike other biophysical profile components, amniotic fluid volume indicates chronic uteroplacental insufficiency. it occurs due to decrease blood flow to the fetal kidney which decreases urine which comprises an amniotic fluid.

Grade 2 amniotic fluid volume defined as

At least one vertical pocket of amniotic fluid measuring 2cm in 2 perpendicular lines.

Grade 0 amniotic fluid volume defined as

No amniotic fluid pocket or a pocket measuring less than 2cm.

Biophysical Profile Interpretation and Management

A score of

  • 10/10 or 8/8 (if not done) – normal score. No intervention needs to take at this point.
  • 8/10 (if Amniotic fluid graded as 0) – it indicates chronic asphyxia. Delivery might be needed.
  • 6/10 and if Amniotic fluid graded as 0 – Deliver the baby.
  • 6/10 and if amniotic fluid graded as 2 – Delivery only if gestational age is greater than 36. If GA is less than 36, repeat the test in 4 – 6 hours and deliver it if persist.
  • 2/10 – Deliver as soon as possible.

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