Biophysical Profile Testing in Late Pregnancy

Female doctor giving pregnant patient an ultrasound

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You're in your third trimester. Your baby may be a few days late, or perhaps there are some risk factors associated with your pregnancy. And so your doctor recommends a Biophysical Profile. The test is painless and comes with very little risk to you or your baby — and it may be an important way to determine whether your baby is as responsive and alert as it should be.

Why Biophysical Profile Testing Is Done

This test can be done in the later stages of pregnancy. It is more frequently used in cases where the mother is going past her assigned due date to ensure fetal well-being. In some cases it is done as a precaution after problems in a previous pregnancy or because of high-risk factors such as previous pregnancy loss in the second half of pregnancy, high blood pressure, diabetes, intrauterine growth retardation (IUGR), Your doctor may also suggest a BPP if you have lupus, kidney disease, or hyperthyroidism.

How the Test Is Done

This test is usually done in your practitioner's office. One of the major parts of the BPP is a detailed ultrasound.

During the ultrasound, the technician is looking for movements of your baby's arms and legs (muscle tone), movements of the body, breathing movements (moving chest muscles), and the measurement of amniotic fluid. The second portion of the test consists of a non-stress test.

Part of the test is intended to observe your baby's movement - but a lack of movement isn't necessarily an issue. Because your baby is just as likely to be asleep as awake, the person doing the test may actually use a buzzer to wake the baby up. 

When the Test Is Done

This test is most frequently done between weeks 38 and 42, however, it can be used as early as the beginning of the third trimester.

How the Results Are Given

Your baby will be scored on five things during the test. A score of 0 (abnormal) or 2 (normal) will be given in each of these categories:

  • Muscle tone
  • Body movements
  • Breathing movements
  • Amniotic fluid levels
  • Heart rate

A score of below 6 is worrisome and action will probably be taken, which may include induction or cesarean section. Six is considered borderline. The test may be repeated as often as daily until the baby is born, though most often it is a one-time event or a weekly event depending on the reason for the biophysical profile.

Risks Involved

The BPP is a noninvasive test that poses few risks to mother or baby. The two most common concerns are a misinterpretation of the data and exposure to ultrasound. Misinterpretation of data may lead to unnecessary induction of labor or even to an unnecessary C-section.

Prenatal exposure to ultrasound not been definitively linked to fetal damage, but because the scan does heat tissue there is a potential risk to be considered.

Where to Go From Here

If the baby is still not as responsive as they would like you may either go to a stress test or even induction or cesarean section.

By Robin Elise Weiss, PhD, MPH
Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor.