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Difficulty: EasyLabor, Delivery, and Puerperium

An otherwise healthy 23-year-old primigravida presents to the labor and delivery unit at 39 weeks gestation reporting regular, painful uterine contractions. Her prenatal course was unremarkable. On admission, her cervix is dilated to 6 cm and 90% effaced, with the fetal vertex at -1 station. Continuous electronic fetal monitoring is initiated. The fetal heart rate tracing demonstrates a baseline of 140/min with moderate variability. There are recurrent, gradual decreases in the fetal heart rate that begin simultaneously with the onset of each contraction. The decelerations reach their nadir exactly at the peak of the contraction, and the heart rate returns to baseline precisely as the contraction ends. Which of the following is the most appropriate next step in management?

  1. A
    Transfer to the operating room for urgent cesarean delivery
  2. B
    Assist the patient into a lateral decubitus posture
  3. Proceed with expectant observation of laborAnswer
  4. D
    Administer a dose of subcutaneous terbutaline
  5. E
    Begin transcervical infusion of normal saline

Answer

Proceed with expectant observation of labor
The patient's fetal heart rate tracing demonstrates early decelerations, which are defined as visually apparent, gradual decreases in the fetal heart rate with a return to baseline associated with a uterine contraction. Crucially, the onset, nadir, and recovery of the deceleration coincide exactly with the beginning, peak, and end of the contraction. This is a physiologic response caused by fetal head compression during a contraction, which leads to altered cerebral blood flow, reflex vagal stimulation, and a subsequent transient decrease in heart rate. Early decelerations are benign and do not indicate fetal hypoxia or acidemia. Therefore, the most appropriate next step in management is expectant observation.

Step-by-Step Solution

1
Analyze the fetal heart rate (FHR) tracing characteristics.
The FHR shows a normal baseline (140/min), moderate variability, and gradual decelerations that perfectly mirror the uterine contractions (nadir of deceleration matches peak of contraction).
Accurate interpretation of the FHR tracing is essential to determine fetal well-being and the need for intervention.
2
Classify the type of deceleration based on its relationship to uterine contractions.
The pattern is identified as early decelerations.
Gradual decreases in FHR (onset to nadir ≥ 30 seconds) that occur simultaneously with contractions represent early decelerations.
3
Determine the underlying pathophysiology and appropriate management.
Early decelerations are caused by fetal head compression, which triggers a reflex vagal response. They are benign and require no intervention.
Recognizing benign physiologic responses prevents unnecessary and potentially harmful obstetric interventions.

Key Concept

Early fetal heart rate decelerations are a benign physiologic response to fetal head compression and require expectant management without intervention.
Estimated Time:1m 0s
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Topics

Labor, Delivery, and Puerperium

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