Biophysical profiles are a form of test used to assess fetal wellbeing, usually performed during the third trimester. This test was developed by Dr. Frank Manning, an obstetrician who practiced in Winnipeg before moving to New York. It has been in use for approximately 30 years and is a relatively simple, risk free procedure that can provide important information on fetal wellbeing.
What Does the Test Entail?
The answer is simpler than you may have thought and involves two procedures you are likely familiar with; a prenatal ultrasound and fetal heart monitoring. The biophysical profile assesses four fetal characteristics and amniotic fluid volume. Each characteristic component is given a score of two points if the component is normal, or zero if the component is abnormal. The score for each component are added together to get a cumulative score out of 10.
Fetal Heart Monitoring
This test records the fetal heart at a time when the mother is not experiencing contractions. This type of fetal heart monitoring is often referred to as a non-stress test because it is done when the fetus is not under the stress of contractions. The fetal heart tracings are analyzed by an obstetrician who will then grade the tracing as normal (2) or abnormal (0).
The other four variables are assessed by way of a prenatal ultrasound. Your obstetrician will be looking for evidence of fetal breathing movements, fetal activity/gross body movements, fetal muscle tone evidenced by your fetus bending and straightening limbs or trunk, and an assessment of the quantity of amniotic fluid. Low amniotic fluid, medically referred to as oligohydramnios, is of particular concern in and of itself which may require further testing or induction of labour if the pregnancy is close to term.
Significance of Biophysical Profile Score
A score of 10/10 on a biophysical profile is evidence of a normal healthy developing fetus. A score of 8/10 with normal amniotic fluid is also reassuring. However, if there is evidence of low amniotic fluid, or if there is a biophysical score of 6/10 or lower, your obstetrician should consider increased surveillance with the possibility of inducing for early delivery.
Modified Biophysical Profile
A biophysical profile is a valuable test used to evaluate fetal wellbeing. It takes about 30 minutes and is performed by an obstetrician. While a biophysical profile assesses five discrete biophysical variables, a simpler and quicker test called a modified biophysical profile assesses only two variables; the fetal heart rate pattern and the amniotic fluid volume.
Written by Joe Miller, QC