What qualifies as a score of 2 for the tone parameter in a biophysical profile?

In the context of a biophysical profile, a score of 2 for the tone parameter indicates a normal finding related to fetal muscle tone and movement. Specifically, an episode of active extension followed by a return to flexion demonstrates healthy neuromuscular function and a well-developed central nervous system in the fetus. This active movement pattern is a sign that the fetus is engaging in normal motor activities, which is critical for assessing fetal well-being.

Active extension and subsequent return to flexion is an essential aspect of fetal health because it reflects the ability of the fetus to move and respond to stimuli, indicative of adequate oxygenation and neurologic function. This score provides reassurance regarding the fetus's condition, as it suggests that the fetus is not only alive but also showing signs of functional muscle tone and nervous system activity.