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Difficulty: MediumLabor, Delivery, and Puerperium

A healthy 24-year-old gravida 1 para 0 at 39 weeks gestation is admitted to the maternity ward in spontaneous active labor. Her prenatal course was uncomplicated. She is currently utilizing continuous epidural analgesia and reports excellent pain control. Her temperature is 37.1°C (98.8°F), blood pressure is 120/76 mmHg, and pulse is 82/min. Uterine contractions are occurring every 3 to 4 minutes and feel firm on palpation. A sterile vaginal examination reveals the cervix is 8 cm dilated and 100% effaced, with the fetal vertex at +1 station. Continuous electronic fetal monitoring demonstrates a baseline heart rate of 145/min with moderate variability. During each uterine contraction, the fetal heart rate trace exhibits a gradual, symmetrical decrease to a nadir of 120/min. The nadir of the heart rate precisely aligns with the peak of the contraction, and the heart rate smoothly returns to baseline simultaneously with the resolution of the contraction. Which of the following is the most appropriate next step in management?

  1. Continue routine intrapartum careAnswer
  2. B
    Administer maternal supplemental oxygen and reposition laterally
  3. C
    Initiate a transcervical amnioinfusion
  4. D
    Administer subcutaneous terbutaline
  5. E
    Prepare for an emergent cesarean delivery

Answer

Continue routine intrapartum care
The correct answer involves continuing expectant management because the patient is exhibiting early decelerations. Early decelerations are defined by a gradual decrease in fetal heart rate (onset to nadir taking ≥\geq 30 seconds) that is symmetrical and mirrors the uterine contraction. Crucially, the nadir of the deceleration occurs exactly at the peak of the contraction. This is a benign, physiologic reflex triggered by compression of the fetal head as it descends into the birth canal (consistent with this patient's 8 cm dilation and +1 station). Because this pattern does not indicate fetal hypoxia or acidemia, it is classified as a Category I tracing, and no medical or surgical intervention is indicated.

Step-by-Step Solution

1
Analyze the fetal heart rate (FHR) tracing described in the vignette.
The tracing shows a gradual, symmetrical decrease matching the contraction, with the nadir aligning exactly with the contraction peak.
Identifying the timing of the deceleration relative to the contraction distinguishes between early, late, and variable decelerations.
2
Correlate the FHR pattern with its underlying pathophysiology.
This pattern defines early decelerations, which are caused by fetal head compression leading to a vagal response.
Understanding the etiology confirms whether the finding is a sign of fetal distress or a normal part of labor.
3
Determine the necessary clinical intervention based on the physiological nature of the decelerations.
Since early decelerations are benign and do not indicate hypoxia, expectant management is required.
Intervening for a normal physiological process introduces unnecessary risk to both mother and fetus.

Key Concept

Early decelerations are benign, gradual decreases in fetal heart rate that precisely mirror uterine contractions, caused by fetal head compression during descent, and require only routine expectant management.
Estimated Time:1m 0s
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Topics

Labor, Delivery, and Puerperium

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