Chapter 185 Biophysical Profile
THE CHALLENGE
Scope of the Problem: Of pregnancies, 3% to 12% are at risk because of gestations that extend beyond term and more may be compromised by maternal disease states that affect fetal health or placental function (e.g., hypertension, diabetes), resulting in abnormalities of fetal growth and amniotic fluid volume and other problems.
TACTICS
Relevant Pathophysiology: The biophysical profile is based on fetal heart rate response to activity (as in the nonstress test) but also adds the assessment of fetal tone, activity, and breathing as evaluated by ultrasonography. These parameters of activity often reflect the impact of acute and subacute stress. The volume of amniotic fluid (also measured by ultrasonography) can be indicative of fetal risk in that reductions are often associated with either maternal or fetal compromise (most often reduced fetal urine output in the face of chronic stress).
Strategies: The biophysical profile is made up of five assessments of fetal well-being: the volume of amniotic fluid present, the frequency of fetal breathing movements, fetal tone, gross body movements, and the results of a nonstress test. Each parameter is scored as present or absent (0 or 2 scale) and then scores are totaled. A score of 8 or 10 is considered normal; 6 is equivocal and suggests further evaluation; and a score of 4 or less is abnormal and augurs for immediate intervention. A score of 0 is invariably associated with significant fetal acidemia.
