A 32-year-old primigravida client at 38 weeks gestation is admitted to the labor and delivery unit in active labor. Her cervix is 7 cm dilated, 70% effaced, and the fetal head is at 0 station. The fetal heart rate shows a baseline of 150 bpm with moderate variability. During a contraction, the nurse observes a gradual decrease in fetal heart rate that begins after the peak of the contraction and returns to baseline after the contraction ends. What is the priority nursing intervention?

Late decelerations indicate uteroplacental insufficiency. Priority intervention is changing to left lateral position and administering oxygen to improve fetal oxygenation by enhancing maternal hemodynamics and oxygen delivery.

Understanding the Fetal Heart Rate Pattern

The fetal heart rate (FHR) tracing described—a gradual decrease in FHR that begins after the peak of the contraction and returns to baseline after the contraction ends—is a classic description of a late deceleration. This pattern is significant because it reflects uteroplacental insufficiency. During a contraction, blood flow through the intervillous space is momentarily reduced. A healthy fetus with adequate placental reserve can tolerate this transient decrease in oxygenation. However, when the placenta is not functioning optimally, the fetus experiences a delayed drop in oxygen levels, which triggers chemoreceptor-mediated vagal slowing of the heart rate only after the peak of the contraction. The return to baseline after the contraction ends reflects the delayed restoration of adequate oxygenation.

The baseline FHR of 150 bpm with moderate variability is reassuring, indicating that the fetal central nervous system is not acidotic at this moment. However, the presence of recurrent late decelerations is a warning sign that the fetal reserve is being compromised and that the pattern could deteriorate, leading to a nonreassuring fetal heart rate status (NRFHRS). A systematic review and meta-analysis on NRFHRS highlights that such patterns are associated with adverse immediate outcomes for the newborn, making timely recognition and intervention critical to prevent fetal hypoxia and acidosis ^[2].

Prioritizing Nursing Interventions

The priority nursing intervention for late decelerations is to improve uterine blood flow and increase maternal oxygenation, which directly addresses the underlying problem of uteroplacental insufficiency. The correct sequence of independent nursing actions is:

1. Change the client's position to a left lateral position. This displaces the gravid uterus off the maternal great vessels (aorta and inferior vena cava), which immediately improves venous return, maternal cardiac output, and consequently, blood flow to the placenta. This is the single most effective and rapid intervention to enhance fetal oxygenation.
2. Administer oxygen via a non-rebreather face mask at 8–10 L/min. Increasing the maternal fraction of inspired oxygen (FiO2) elevates the partial pressure of oxygen in maternal blood, creating a larger diffusion gradient across the placenta to the fetus. This helps correct the fetal hypoxemia that is causing the late decelerations.

These actions are the first-line, nurse-initiated interventions that can quickly resolve the abnormal pattern. A study on nursing interventions during delivery reinforces that proactive nursing management, including position changes and supportive care, has a profound beneficial influence on labor progression and maternal-fetal well-being .

Why the Other Options Are Not the Priority

- Document the findings and continue routine monitoring (Option 1): This is incorrect because late decelerations are an abnormal, potentially ominous pattern that requires immediate intervention, not just observation. While documentation is essential, it is not the priority action when the fetus is showing signs of compromise. The standard of care for intermittent auscultation, the gold standard for fetal assessment in uncomplicated labors, mandates a clear response protocol for abnormal findings, which goes beyond simple documentation .

- Immediately notify the healthcare provider (Option 2): While the provider must eventually be notified, this is not the first action. The nurse should first implement independent interventions to correct the pattern. If the late decelerations persist despite position change and oxygen administration, then immediate notification is warranted, as it may indicate a need for expedited delivery. Delaying direct interventions to make a phone call could worsen fetal hypoxia.

- Prepare for immediate cesarean delivery (Option 4): This is premature. Late decelerations can often be corrected with conservative nursing interventions. Preparation for cesarean delivery is the next step if the pattern does not resolve with intrauterine resuscitation measures (position change, oxygen, IV fluid bolus) and is accompanied by other nonreassuring signs like loss of variability or new-onset tachycardia. The presence of moderate variability in this scenario suggests the fetus is not yet severely acidotic, providing a window for these interventions to work.