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Question

Difficulty: Very hardLabor, Delivery, and Puerperium

A 24-year-old primigravid patient at 40 weeks gestation is evaluated on the labor and delivery unit. She has been in the second stage of labor and actively pushing for the past 2 hours under continuous epidural analgesia. Until recently, the fetal heart rate tracing demonstrated a baseline of 140/min, moderate variability, and positive accelerations without decelerations. However, 4 minutes ago, the fetal heart rate suddenly decreased to 80/min and has remained at this rate. Uterine contractions are occurring every 3 minutes and lasting 45 seconds. Maternal repositioning to the left lateral decubitus position, administration of a rapid intravenous fluid bolus, and discontinuation of oxytocin were immediately performed, but the fetal heart rate remains at 80/min. Cervical examination reveals complete dilation and 100% effacement. The fetus is in a vertex presentation, the position is direct occiput anterior, and the station is +3. The estimated fetal weight is 3,300 g. Which of the following is the most appropriate next step in management?

  1. Perform a vacuum-assisted vaginal deliveryAnswer
  2. B
    Proceed with an emergency cesarean delivery
  3. C
    Administer intravenous terbutaline
  4. D
    Initiate a transcervical amnioinfusion
  5. E
    Continue maternal pushing and observe for fetal heart rate recovery

Answer

Perform a vacuum-assisted vaginal delivery
The patient is experiencing a prolonged fetal heart rate deceleration that has not responded to initial intrauterine resuscitative measures. Immediate delivery is indicated to prevent fetal hypoxic-ischemic injury. The fetus is at a +3 station (well-engaged and low in the pelvis), the cervix is completely dilated, and the position is direct occiput anterior. These clinical factors perfectly fulfill the prerequisites for an operative vaginal delivery. In this scenario, applying a vacuum or forceps is the fastest, safest method to achieve immediate delivery, avoiding the critical time delay and surgical risks associated with a cesarean delivery.

Step-by-Step Solution

1
Evaluate the fetal heart rate tracing.
The tracing shows a prolonged deceleration to 80/min lasting for over 4 minutes that is unresponsive to resuscitative measures (Category III).
Identifying a Category III tracing dictates that immediate delivery must be accomplished to prevent severe fetal acidemia.
2
Assess the progress of labor and current maternal/fetal anatomical relationship.
The patient is fully dilated, 100% effaced, and the fetal head is in a direct occiput anterior position at a +3 station.
The station and dilation determine the safest and most rapid mode of immediate delivery.
3
Determine the optimal route of immediate delivery based on the assessment.
Operative vaginal delivery (vacuum or forceps) is selected.
At a +3 station, the fetal head is at the pelvic floor. Operative vaginal delivery can be accomplished in minutes, whereas setting up for a cesarean delivery takes longer and poses significant surgical risks for extracting a deeply engaged head.

Key Concept

In the setting of a Category III fetal heart rate tracing requiring immediate delivery during the second stage of labor, an operative vaginal delivery is the preferred next step if the fetal head is well-engaged (+2 station or lower) and all prerequisites are met.
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Topics

Labor, Delivery, and Puerperium

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