Biophysical Profile: Risks and Side Effects
The biophysical profile combines an ultrasound evaluation with a non-stress test (NST) and is intended to determine fetal health during the third trimester. This biophysical profile is performed if there is a question about fetal health and well being resulting from either an examination, maternal/fetal symptoms, or if the pregnancy is considered high risk.
How is a BPP Performed?
There are two parts to the BPP, a Non-stress Test (NST) and an ultrasound evaluation. The NST involves attaching one belt to the mother’s abdomen to measure fetal heart rate, and another belt to measure contractions. Movement, heart rate and “reactivity” of heart rate to movement are measured for 20-30 minutes.
If the baby does not move for a time during the test, it does not mean there is a problem; the baby may be asleep.
A nurse may use a small “buzzer” to wake the baby for the remainder of the test. The ultrasound portion of the test is like any other obstetrical ultrasound performed during pregnancy and is performed by a qualified ultrasound technician who is usually overseen by a perinatologist.
The ultrasound may take up to an hour, and the technician will watch for a variety of signs that are important in measuring the health of your baby.
What does the BPP look for?
Usually, five specific fetal attributes are studied and “scored” during the BPP:
|Breathing||1 breathing episode within 30 minutes||No breathing episodes within 30 minutes|
|Movement||2 or more movements within 30 minutes||less than 2 movements within 30 minutes|
|Muscle Tone||1 or more episodes of active extension/flexion of limbs, etc. (i.e. opening and closing a hand).||Slow extension/flexion of limbs, partially open fetal hand, etc|
|Heart Rate||2 or more episodes of reactive heart rate acceleration within 20 min||1 or more episodes of unreactive heart rate acceleration|
|Amniotic Fluid||1 or more adequate pockets of fluid||Either no pockets or inadequate pockets of fluid|
The total score will help decide the overall health and well being of your baby and help your doctor or midwife determine if your baby should be delivered sooner than planned.
What are the risks and side effects to the mother or baby?
The BPP is a non-invasive test that poses no known risks or side effects to the mother or baby, although it should be noted some concern has been raised on ultrasounds that are done for lengthy periods of time.
When is a BPP performed?
A BPP is generally performed after 32 weeks of gestation.
Compiled using information from the following sources:
2. Biophysical Profiles, American Family Physician (1999),
Biophysical Profile: Ultrasound, Peter A. Gearhart, MD, (2005)