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Zorluk: Çok zorLabor, Delivery, and Puerperium

A 2828-year-old G1P0 at 3939 weeks gestation is evaluated in the labor and delivery unit. At 10:00 AM10:00\text{ AM}, her cervical examination reveals 6 cm6\text{ cm} dilation, 100%100\% effacement, and the fetal head at 00 station. Artificial rupture of membranes is performed, yielding clear fluid. Due to a previous period of slow cervical change, an intrauterine pressure catheter (IUPC) is placed and an intravenous oxytocin infusion is started.

By 2:00 PM2:00\text{ PM} (44 hours later), her cervical examination remains completely unchanged at 6 cm6\text{ cm} dilation, 100%100\% effacement, and 00 station. Review of the IUPC tracing over the last hour shows 55 contractions per 1010 minutes. The contractions have peak pressures of 65 mm Hg65\text{ mm Hg} and a resting tone of 15 mm Hg15\text{ mm Hg}. The fetal heart rate tracing shows a baseline of 140/min140\text{/min}, moderate variability, and no decelerations. Which of the following is the most appropriate next step in management?

  1. Cesarean deliveryCevap
  2. B
    Continue expectant management for 22 more hours
  3. C
    Increase the oxytocin infusion rate
  4. D
    Operative vaginal delivery
  5. E
    Prophylactic amnioinfusion

Cevap

Cesarean delivery
The correct answer is cesarean delivery. This patient meets the diagnostic criteria for active phase arrest. According to ACOG guidelines, active phase arrest in the first stage of labor is defined as a maternal cervix dilated to ≥6 cm\geq 6\text{ cm} with ruptured membranes, and no cervical change for either ≥4\geq 4 hours with adequate contractions (>200>200 Montevideo units) or ≥6\geq 6 hours with inadequate contractions. This patient's Montevideo units are calculated by subtracting the resting tone (15 mm Hg15\text{ mm Hg}) from the peak pressure (65 mm Hg65\text{ mm Hg}) to get the amplitude (50 mm Hg50\text{ mm Hg}), and multiplying by the number of contractions in 1010 minutes (55). This yields 250 MVUs250\text{ MVUs}, which is adequate. Because she has had adequate contractions for 44 hours with no cervical change, she has active phase arrest and requires a cesarean delivery.

Adım Adım Çözüm

1
Calculate the Montevideo units (MVUs) to determine contraction adequacy.
Amplitude = Peak (65 mm Hg65\text{ mm Hg}) - Resting tone (15 mm Hg15\text{ mm Hg}) = 50 mm Hg50\text{ mm Hg}. With 55 contractions per 1010 minutes, total MVUs = 5×50=250 MVUs5 \times 50 = 250\text{ MVUs}.
Accurate assessment of labor progression requires knowing if contractions are adequate (>200 MVUs>200\text{ MVUs}).
2
Evaluate the patient's labor progress against ACOG diagnostic criteria for active phase arrest.
The patient is at ≥6 cm\geq 6\text{ cm} dilation with ruptured membranes. She has had no cervical change for 44 hours despite adequate contractions (250 MVUs250\text{ MVUs}).
Active phase arrest criteria distinguish between patients who need more time or oxytocin and those who require surgical intervention.
3
Determine the definitive management for active phase arrest.
Cesarean delivery is indicated.
Once active phase arrest is diagnosed, further expectant management or uterotonic administration is futile and increases maternal and fetal morbidity.

Anahtar Kavram

Active phase arrest in the first stage of labor is diagnosed at ≥6 cm\geq 6\text{ cm} dilation with ruptured membranes and no cervical change for ≥4\geq 4 hours with adequate contractions (>200 MVUs>200\text{ MVUs}) or ≥6\geq 6 hours with inadequate contractions.
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Konular

Labor, Delivery, and Puerperium

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