A biophysical profile (BPP) ultrasound is a non-invasive prenatal test used to assess a fetus’s well-being. It evaluates various physiological and physical indicators, providing valuable insights without posing risks to either the pregnant individual or the developing baby. This painless test is typically performed in the later stages of pregnancy.
Understanding the BPP Ultrasound
A biophysical profile ultrasound combines two primary methods to evaluate fetal health: an ultrasound examination and a non-stress test (NST). The term “biophysical profile” refers to the evaluation of both biological (physiological) and physical aspects of the fetus.
The ultrasound portion assesses four specific biophysical variables, while the non-stress test monitors the fetal heart rate. These five components provide a detailed picture of how the fetus is functioning. The BPP is a scoring system, where each observed parameter contributes to an overall score reflecting fetal well-being.
Reasons for a BPP Ultrasound
A biophysical profile ultrasound is recommended when there are concerns about fetal health or when a pregnancy is considered high-risk. For instance, a BPP may be ordered to investigate a noticeable decrease in fetal movement.
Maternal health conditions can also prompt a BPP, including diabetes, high blood pressure (hypertension), or preeclampsia. Other reasons include pregnancies that extend beyond the due date, carrying multiple babies, or if there’s too much or too little amniotic fluid. The BPP helps determine if the baby is receiving sufficient oxygen and if continued pregnancy is safe.
The BPP Procedure and Components
Undergoing a biophysical profile involves two main parts: a non-stress test and an ultrasound scan. During the non-stress test, two elastic belts with sensors are placed around the abdomen to monitor the fetal heart rate and uterine contractions. If the baby is quiet, a buzzer might be used to encourage movement and heart rate acceleration.
The ultrasound component assesses four specific parameters of fetal activity and environment:
Fetal breathing movements: The technician looks for episodes of the baby’s chest wall moving, mimicking breathing.
Gross body movements: Observed by noting three or more distinct body or limb movements within a 30-minute period.
Fetal tone: Evaluated by watching for active extension and flexion of limbs or the opening and closing of hands.
Amniotic fluid volume: Measured, looking for a vertical pocket of fluid at least 2 centimeters deep.
Interpreting Your BPP Results
The results of a biophysical profile are presented as a score out of 10. Each of the five components—fetal heart rate (from the NST), breathing movements, gross body movements, fetal tone, and amniotic fluid volume—receives either 0 or 2 points. A score of 10 indicates that the fetus is healthy and well-oxygenated.
A score of 8 or 10 is considered reassuring, suggesting no immediate concerns. If the score is 6, it is considered equivocal or borderline, and a repeat BPP within 24 hours or further testing may be recommended. A score of 4 or less is considered abnormal, indicating potential problems and may lead to closer monitoring or immediate delivery, depending on gestational age. Discuss these results with a healthcare provider to understand their implications for the pregnancy.