Which fetal monitoring pattern is most associated with decreased placental perfusion during contractions?

• A. Early decelerations
• B. Late decelerations
• C. Variable decelerations
• D. Tachycardia

Answer: (B)

When placental perfusion is reduced during contractions, the fetus experiences transient hypoxia that shows up as late decelerations on the monitor. These decelerations begin after the contraction starts and recover after the contraction ends, signaling uteroplacental insufficiency. This pattern is the classic indicator that placental blood flow is compromised during the labor contraction.

Early decelerations, in contrast, are usually due to head compression and mirror the contraction. Variable decelerations are abrupt drops from cord compression and aren’t tied to the timing of contractions. Tachycardia is an elevated fetal heart rate, not a deceleration pattern related to placental perfusion.