Inpatient Obstetric Nurse (NCC) Practice Exam

How is a nonreactive NST at term defined?

1. No accelerations in 20 minutes

2. No accelerations meeting the 15x15 criteria in 40 minutes

3. No accelerations or decelerations within 30 minutes

4. One acceleration in 40 minutes

The correct answer is: No accelerations meeting the 15x15 criteria in 40 minutes

A nonreactive nonstress test (NST) at term is defined by the absence of accelerations meeting the 15x15 criteria within a specified time frame, which is 40 minutes in this context. The 15x15 criteria refer to an increase in the fetal heart rate of at least 15 beats per minute (bpm) above the baseline, lasting for a minimum of 15 seconds. This criteria is important because it indicates that the fetus is receiving enough oxygen and is reacting appropriately to its environment; the absence of these accelerations could indicate fetal distress or a potential underlying issue that warrants further investigation. When conducting an NST, a reaction is desirable, as it demonstrates fetal well-being. The 40-minute time frame allows sufficient observation for the identification of any accelerations that might occur. If there are no accelerations that fit the 15x15 criteria within this period, it suggests that further evaluation may be necessary to assess the health of the fetus. This is why the correct answer highlights the specific parameters and time frame used to define a nonreactive NST at term, making it essential for clinical practice in monitoring fetal health.