Biophysical Profile

The BPP consists of five key components that are scored during the test:

1. Fetal Heart Rate (Non-Stress Test or NST)

• The non-stress test is a monitoring of the fetus’s heart rate in response to its movements. It involves attaching small sensors to the mother’s abdomen to detect the fetal heart rate and movements.
• A reactive NST is considered normal when the heart rate increases at least two times for 15 seconds during a 20-minute period in response to fetal movements. This indicates the fetus is receiving enough oxygen and is generally healthy.
• If the fetal heart rate does not respond appropriately, further tests or monitoring may be needed.

2. Fetal Movement

• This measures the fetus’s overall movement, including the frequency of limb or body movements. A healthy fetus will typically move several times within a 30-minute period.
• Normal fetal movement is an indication that the nervous system and muscles are functioning properly.
• Score: A fetus that moves at least 3 times in 30 minutes typically scores 2 points (normal), while fewer movements would score 0 points.

3. Fetal Tone

• Fetal tone refers to the muscle tone or movement of the fetus’s limbs and body. The test looks for flexion and extension of the limbs and the movements of the body (such as the opening and closing of the hands).
• A normal score indicates that the fetus is able to control its muscles, suggesting good neurological health.
• Score: 2 points are awarded if there is at least one instance of normal tone (such as flexion and extension of limbs). 0 points are given if there is no normal tone.

4. Fetal Breathing Movements

• This component evaluates the fetus’s ability to breathe in utero, specifically the movement of the diaphragm as the fetus practices breathing. This helps assess the maturity of the lungs and the overall well-being of the fetus.
• A normal result shows that the fetus is able to practice breathing, which indicates lung development.
• Score: The fetus is given 2 points if it demonstrates at least one episode of breathing movements lasting 30 seconds or more within a 30-minute window. 0 points are given if no breathing movements are observed.

5. Amniotic Fluid Volume (AFV)

• This measures the amount of amniotic fluid around the fetus. Amniotic fluid plays a crucial role in protecting the fetus, allowing it to move and providing nutrients and waste removal.
• The amount of amniotic fluid is assessed using ultrasound by measuring pockets of fluid in the uterus.
• Score: A normal amount of fluid (usually 2 to 8 cm in the amniotic fluid index or AFI) is given 2 points, while a low or absent amount of fluid (oligohydramnios) may score 0 points.

Scoring the Biophysical Profile (BPP):

The BPP uses a score of 0 to 10, based on the five components assessed:

• Each of the five components is scored as either 0 or 2 (0 being abnormal or absent, 2 being normal).
• The scores are added together to produce a total score, with a maximum possible score of 10 points.
  • Score of 8–10: Generally considered reassuring, indicating that the fetus is healthy and well-oxygenated.
  • Score of 6: May indicate some potential problems and will likely require further testing or closer monitoring. The doctor might recommend additional testing or may opt to deliver the baby, depending on how far along the pregnancy is.
  • Score of 4 or less: Often a sign of concern and may indicate fetal distress or a risk of complications. A score of 4 or lower may suggest the need for urgent delivery or additional interventions.

Indications for a Biophysical Profile (BPP):

The BPP is usually performed when there are concerns about the fetus’s health. Common indications include:

• Post-term pregnancy (pregnancy extending beyond 40 weeks).
• Maternal health issues like high blood pressure, diabetes, or preeclampsia.
• Fetal growth restriction (FGR) or if the baby is measuring smaller than expected.
• Reduced fetal movements.
• Intrauterine growth restriction (IUGR) or other concerns about fetal growth.
• Previous pregnancy complications, such as stillbirth or other adverse outcomes.
• Chronic conditions in the mother (e.g., kidney disease, heart disease, or autoimmune disorders).
• Abnormal results from previous ultrasounds or non-stress tests (NST).

When is a Biophysical Profile Performed?

• Timing: The BPP is usually done during the third trimester, but it may be recommended earlier in certain high-risk pregnancies or if there are concerns about fetal well-being. It’s commonly performed weekly or bi-weekly in high-risk pregnancies, particularly near the end of the pregnancy (around 32 to 40 weeks).
• It may be repeated periodically to monitor the baby’s health and ensure that any potential issues are identified early.

Advantages of the Biophysical Profile:

• Non-invasive: Like other ultrasounds, the BPP does not require any invasive procedures, making it a safe way to monitor the fetus.
• Comprehensive: By combining multiple tests (NST and ultrasound), it provides a detailed view of the baby’s overall health, including heart function, movement, breathing, and the amniotic fluid level.
• Early Detection of Problems: The BPP helps detect early signs of fetal distress, allowing for timely intervention to prevent further complications.

Limitations of the Biophysical Profile:

• False Positives/Negatives: Like all tests, the BPP is not perfect. It can sometimes produce false positives (indicating a problem when there is none) or false negatives (not detecting a problem when there is one).
• Interpretation: While a score of 8-10 is reassuring, a lower score may not always indicate an immediate threat, and further testing may be needed to understand the full picture.

In Summary:

The Biophysical Profile (BPP) is a useful and non-invasive prenatal test that evaluates the health and well-being of the fetus, combining a non-stress test (NST) and ultrasound. It assesses five components: fetal heart rate, fetal movement, fetal tone, fetal breathing, and amniotic fluid volume. The BPP is typically performed when there are concerns about fetal health, particularly in high-risk pregnancies, and helps guide decisions regarding the management of the pregnancy and possible interventions. A normal BPP score suggests the fetus is healthy, while an abnormal score may warrant further monitoring or action.