Biophysical Profile: Procedure, Risks & Side Effects
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With advancements in medical technologies, it is now easier to perform tests that determine your baby’s health in the womb. The biophysical profile is a medical procedure that is performed to assess your baby’s growth and health when it is in the womb; it helps explicitly in checking whether the baby in the womb is getting enough oxygen or not. Biophysical profiling is done to check the general wellbeing of the baby in case of high-risk pregnancies. It is a non-invasive and a painless procedure, and is globally accepted to track the baby’s health.
What Is a Biophysical Profile?
A biophysical profile (BPP) is a combination of biophysical profile ultrasound and a non-stress test (NST). It is advised only if the gynaecologist sees a potential risk or complication in the pregnancy. It is done after 28 weeks of pregnancy. It shows the baby’s heart rate, breathing, movements, tone, and the level of the amniotic fluid present. Following are some of the attributes that are checked during a biophysical profile:
- Foetal Breathing: It shows how your baby’s chest moves as he breathes.
- Foetal Heart Rate: It indicates the number of heartbeats per minute.
- Foetal Movement: It records the number of movements your baby makes in 30 minutes but sometimes if the baby is asleep, it takes longer than 30 minutes.
- Foetal Tone: It shows the ability of the baby to flex and extend an arm or leg, measured by counting quick and jerky movements.
- The Volume of Amniotic Fluid: The amount of amniotic fluid surrounding your baby.
Who Should Opt for a BPP Test? When Should It Be Done?
It is usually performed if it is a high-risk pregnancy, overshot due date, twins, or maternal high blood pressure or heart disease. It is also done in unstable pregnancies or with progressive foetus deterioration. Here are some other reasons for getting a biophysical profile test:
- You are a diabetic and on medication.
- You are experiencing other medical conditions, which might affect your pregnancy.
- You are experiencing gestational hypertension.
- Your baby is showing weak growth and appears smaller.
- Your baby is not very active.
- Your levels of amniotic fluid are not appropriate. It is either more or less than the normal range.
You’ve crossed the due date, and the doctor wants to understand how the baby is pulling along.
- You have a history of losing a baby during the third trimester of pregnancy for unknown reasons, and the doctor wants to double-check this time to ensure everything is fine to avoid the chances of a repeated miscarriage.
- You or the baby has a condition, which requires monitoring.
Although it is done during the third trimester, it is purely the doctor’s call to do the BPP test or not.
There are two parts to a BPP. One of the tests is a non-stress test (NST), and the other is an ultrasound evaluation. These tests are usually done with a full bladder; the mother is asked to drink a few glasses of juice or water (6-7 glasses). This helps in pushing the intestines out of the way to a get a clearer picture of the baby. In full-term pregnancies, it might be needed on a full bladder, as the baby itself pushes the intestines out of the way.
For an NST, you must lie on your left side. It involves one belt strapped to the abdomen of the mother to measure the foetal heart rate, and another belt to measure the contractions. These parameters are measured for 20-30 minutes. If the baby is not moving or is asleep, a buzzer is used to wake up the baby, then the ultrasound is done by a skilled and qualified technician supervised by a perinatologist. This ultrasound might take about an hour. It is used to observe the body movements of the baby, flexing the arms and legs, also referred to as muscle tone, the baby’s capability to move its chest muscles and diaphragm for breathing, and the quantity of the amniotic fluid. The ultrasound test is similar to the obstetrical ultrasound, which is performed during pregnancy.
Risks and Side Effects
There are no potential side effects of this procedure since it is non-invasive, but the only concern is the prolonged exposure to ultrasound. The mother’s anxiety might cause some deviations in the parameters, especially while doing the non-stress test. Hence, it is advised that you stay relaxed for the entire duration of the procedure.
What Does a Biophysical Profile Test Result Mean?
A BPP in pregnancy has five specific foetal parameters that are studied and “scored” during the procedure:
|Breathing||1 breathing episode within 30 minutes||No breathing episodes within 30 minutes|
|Movement||2 or more limb movements within 30 minutes
(active continuous movements are considered as one single movement)
|Less than 2 limb movements within 30 minutes|
|Muscle Tone||1 or more episodes of active extension/flexion of limbs, and so on (for example, opening and closing a hand is considered as one tone)||Slow extension/flexion of limbs, partially open fetal hand, and so on|
|Heart Rate||2 or more episodes of reactive heart rate acceleration within 20 minutes||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|
Every movement tested in the BPP is a result of efferent signals that are originating in different central nervous system (CNS) centres. It matures at various gestational ages. The total score is used by your doctor to determine the health of the baby.
The BPP profile ultrasound technician (sonographer) assigns a score of 0 – 2 for each parameter. A score of 8 or above is good; anything less than that is a cause for concern. If the score is 6, then the BPP scan needs to be repeated within 24 hours. If the score is 4 or less, there might be a need to deliver the baby immediately. Sometimes, even if the scores are fine, the amniotic fluid levels might need monitoring. Depending on the stage of the pregnancy, delivery might be advised.
An abnormal pattern can be noticed in the umbilical cord blood flow followed by reduced FHR (foetal heart rate) and the loss of breathing. The movements of the foetus and tone are the last parameters that show abnormalities. If the abnormalities are closer to term, then immediate delivery is done. However, if it is far away from the term, then the comprehensive management of the baby’s health is planned out. This might include weekly or fortnightly testing.
A modified biophysical profile is a combination of the Non-Stress Test and the evaluation of the amniotic fluid levels. It is a more efficient version of the biophysical profile. If the amniotic fluid levels are less, it indicates that the baby is not making enough urine or the placenta might not be functioning properly. If either the NST or Amniotic Fluid Volume (AFV) is abnormal, then the complete BPP is performed along with contract stress test (CST).
A study titled “The antenatal measurement of foetal urine production” mentions that “two mechanisms help to explain the relationship between decreased AFV and perinatal morbidity and mortality. Decreased fluid may reflect uteroplacental insufficiency, especially in growth-retarded and postdate foetuses.”
The bpp scan cost is not very high. However, it varies from hospital to hospital. Speak to the radiologist before consenting to the procedure.
A biophysical profile is a standard tool that helps the doctor to monitor the baby and possibly prevent fetal distress. It is a tool for providing antenatal fetal surveillance. The false-negatives in BPP is very low (0.77 mortality per 1000 babies), and hence it’s a reliable procedure. When the test results indicate a risk to the growing fetus, the physicians can take measures to intervene and avoid progressive metabolic acidosis, which can result in death.
Also Read: Foetal Echocardiography