All the following are components of biophysical profile except:

The five fetal biophysical components assessed: (1) hea rate acceleration, (2) breathing, (3) movements, (4) tone, and (5) amnionic fluid volume. Normal variables were assigned a score of 2 each, and abnormal variables were given a score of 0. Thus, the highest score possible for a normal fetus is 10. (Ref: William's Obstetrics; 25th edition)