Which NST pattern would prompt further assessment due to potential fetal distress?

• A. Reactive NST
• B. Late decelerations
• C. Normal variability with accelerations
• D. Absence of accelerations in 60 minutes

Answer: (B)

Late decelerations on an NST indicate fetal distress from reduced placental blood flow during contractions, signaling potential hypoxia that requires prompt assessment. They begin after the onset of a contraction and reach their lowest point after the contraction peak, then return to baseline as the contraction ends. This pattern shows the fetus isn’t tolerating labor well, often due to uteroplacental insufficiency.

Immediate actions focus on stabilizing both mother and fetus and correcting reversible factors: place the mother on her left side, discontinue or reduce any oxytocin or other uterotonic agents, ensure adequate IV fluids, provide supplemental oxygen, and monitor the fetal tracing and contractions continuously. Be prepared to escalate care and expedite delivery if the tracing does not improve or worsens.

Reactive NSTs and tracings with normal variability and accelerations are reassuring and do not indicate distress. Absence of accelerations over a prolonged period is concerning and would prompt further assessment, but late decelerations specifically point to potential fetal hypoxia and require urgent evaluation.