Review the following clinical assessments of labor progress. According to current American… — USMLE Step 2 CK

Review the following clinical assessments of labor progress. According to current American College of Obstetricians and Gynecologists (ACOG) guidelines, match each clinical scenario to its correct diagnostic classification.

A nulliparous patient at $40$ weeks gestation with regular uterine contractions has remained at $4$ cm of cervical dilation for $22$ hours.Prolonged latent phase
A multiparous patient at $39$ weeks gestation with spontaneous membrane rupture has remained at $7$ cm of cervical dilation for $4$ hours despite an intrauterine pressure catheter confirming $240$ Montevideo units.Active phase arrest
A nulliparous patient at $38$ weeks gestation with epidural analgesia has been pushing with each contraction for $4$ hours without any descent of the fetal head past the $+1$ station.Second stage arrest
A multiparous patient at $41$ weeks gestation experiences a gradual change in cervical dilation from $6$ cm to $7$ cm over a period of $3$ hours with regular uterine contractions.Protracted active phase

Answer

The correct matches align each clinical presentation with specific ACOG thresholds for labor abnormalities:

22

hours at

4

cm is a Prolonged latent phase;

4

hours at

7

cm with adequate contractions is an Active phase arrest;

4

hours of pushing with an epidural in a nullipara is a Second stage arrest; and slow progression from

6

7

cm over

3

hours is a Protracted active phase.

Labor abnormalities are classified by precise cervical dilation milestones and time thresholds. A latent phase

>20

hours (nullipara) is prolonged. In the active phase (

\ge 6

cm), no change for

4

hours with adequate contractions defines arrest, while slow change constitutes protraction. In the second stage,

4

hours of pushing (nullipara with epidural) defines arrest.

Step-by-Step Solution

Determine the current stage and phase of labor for each patient based on cervical dilation and pushing status.

Dilation less than

6

cm indicates the latent phase; dilation of

6

cm or more indicates the active phase; complete dilation (

10

cm) marks the onset of the second stage.

Labor guidelines apply different time constraints depending on the precise phase of labor.

Compare the elapsed time in the scenario against ACOG diagnostic thresholds for parity and epidural status.

The nulliparous latent phase exceeds the

20

-hour limit. The active phase lack of change meets the

4

-hour adequate contraction rule for arrest. The second stage duration meets the

4

-hour limit for a nullipara with an epidural.

Accurate application of numerical thresholds is required to distinguish between normal labor, protracted labor, and arrested labor.

Key Concept

Abnormalities of Labor Progress and ACOG Diagnostic Criteria

Estimated Time:1m 0s

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