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Difficulty: HardLabor, Delivery, and Puerperium

A 24-year-old primigravid woman at 39 weeks and 2 days gestation is evaluated in the labor and delivery unit due to a non-reassuring fetal heart rate tracing. The patient presented in spontaneous active labor 14 hours ago and has been pushing in the second stage of labor for 2.5 hours. Continuous epidural anesthesia provides excellent pain relief. Over the last 15 minutes, the continuous fetal monitor demonstrates a baseline heart rate of 155/min, absent baseline variability, and recurrent late decelerations. Uterine contractions occur every 3 minutes, last 60 seconds, and are palpated as firm. The nursing staff immediately repositioned the patient to the left lateral decubitus position, administered an intravenous fluid bolus, and applied 100% oxygen via a nonrebreather mask. Subsequent evaluation 10 minutes later shows no improvement in the fetal heart rate tracing. Maternal vital signs are temperature 37.0∘C37.0^\circ\text{C} (98.6∘F98.6^\circ\text{F}), blood pressure 118/74118/74 mm Hg, and pulse 92/min. On physical examination, the cervix is completely dilated and effaced. The fetal sagittal suture is palpable in the anteroposterior diameter with the posterior fontanelle directed anteriorly. The leading bony edge of the fetal skull is at +3+3 station. Which of the following is the most appropriate next step in management?

  1. Operative vaginal deliveryAnswer
  2. B
    Cesarean delivery
  3. C
    Fetal scalp stimulation
  4. D
    Administration of intravenous terbutaline
  5. E
    Continued maternal pushing

Answer

Operative vaginal delivery
The patient's fetal heart rate tracing shows absent variability with recurrent late decelerations, which is a Category III tracing indicating an increased risk of fetal acidemia. When a Category III tracing persists despite intrauterine resuscitative measures (left lateral repositioning, oxygen, intravenous fluids), immediate delivery is strictly mandated to prevent hypoxic-ischemic encephalopathy and fetal death. Because the patient is completely dilated, the fetal head is engaged in a known position (direct occiput anterior), and the station is low (+3), the criteria for an operative vaginal delivery (vacuum or forceps) are met. An operative vaginal delivery can be performed immediately at the bedside and is the fastest, most appropriate route of delivery in this emergency scenario.

Step-by-Step Solution

1
Interpret the continuous fetal heart rate tracing.
The tracing demonstrates absent baseline variability with recurrent late decelerations, which defines a Category III fetal heart rate tracing.
Accurate interpretation is critical for determining the risk of fetal acidemia and the urgency of intervention.
2
Assess the fetal response to initial intrauterine resuscitation.
The Category III tracing persists despite appropriate resuscitative measures including maternal repositioning, intravenous fluids, and supplemental oxygen.
A persistent Category III tracing is highly predictive of abnormal fetal acid-base status and mandates immediate delivery.
3
Evaluate the clinical prerequisites to determine the fastest route of delivery.
The physical examination confirms the cervix is completely dilated, the fetal position is direct occiput anterior, and the fetal head is at a low station (+3).
These findings fulfill the strict criteria required for a safe operative vaginal delivery.
4
Select the most appropriate management strategy.
Operative vaginal delivery is chosen over cesarean delivery.
At a +3 station in a fully dilated patient, operative vaginal delivery can be performed immediately at the bedside, whereas cesarean delivery would introduce dangerous time delays.

Key Concept

A persistent Category III fetal heart rate tracing in the second stage of labor mandates immediate delivery; if the fetal head is engaged at a low station (e.g., +2 or +3) with complete cervical dilation, operative vaginal delivery is the fastest and most appropriate intervention.
Estimated Time:1m 30s
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Topics

Labor, Delivery, and Puerperium

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