Uterine Activity Interpretation Flashcards

A nurse is reviewing a 10-minute electronic fetal monitoring strip that shows seven contractions. According to NICHD guidelines, how should the uterine activity be characterized?

Answer: Tachysystole

According to the 2008 NICHD guidelines, tachysystole is defined as more than five contractions in a 10-minute window, averaged over a 30-minute period. Seven contractions in 10 minutes exceeds this threshold. Normal activity is five or fewer contractions. Uterine coupling refers to a specific pattern of paired contractions, and hypertonus refers to an elevated resting tone between contractions, which is not described.

A patient has an intrauterine pressure catheter (IUPC) in place. Over a 10-minute period, there are four contractions. The peak pressures are 60, 65, 70, and 60 mm Hg, and the resting tone is 15 mm Hg. What are the calculated Montevideo Units (MVUs) for this period?

Answer: 200 MVUs

Montevideo Units (MVUs) are calculated by summing the intensity of each contraction in a 10-minute window. Intensity is defined as the peak pressure minus the resting tone. Calculation: (60-15) + (65-15) + (70-15) + (60-15) = 45 + 50 + 55 + 45 = 200 MVUs. A value of 200 MVUs or greater is generally considered adequate for active labor progress.

When assessing uterine contraction intensity via manual palpation of the fundus, which finding corresponds to a 'strong' contraction?

Answer: The uterine wall cannot be easily indented by the examiner's fingertips.

The standard subjective measure for palpating contraction intensity compares the feel of the uterine fundus to parts of the face. A 'strong' contraction is one where the uterine wall is very firm and cannot be indented, similar to the feel of a forehead. 'Mild' is compared to the tip of the nose, and 'moderate' is compared to the chin. A contraction lasting over 2 minutes would be defined as tetanic or prolonged, which is a measure of duration, not intensity.

A laboring patient's EFM tracing shows a pattern of two contractions occurring in rapid succession followed by a longer resting interval before the next pair. Which term best describes this uterine activity pattern?

Answer: Uterine coupling

Uterine coupling is the term used to describe contractions that occur in pairs or doubles. This pattern involves two contractions with a short rest period in between, followed by a longer pause. While it can sometimes be associated with tachysystole if the overall number of contractions is high, the specific pattern described is best defined as coupling.

Which of the following is the primary purpose for measuring Montevideo Units (MVUs) with an Intrauterine Pressure Catheter (IUPC)?

Answer: To assess the adequacy of uterine power for labor progress

The primary clinical use for calculating Montevideo Units (MVUs) is to quantitatively assess the adequacy of uterine contractile power to determine if it is sufficient to produce cervical change and fetal descent during the active phase of labor. Generally, MVUs of 200 or more are considered adequate. While an IUPC helps assess frequency and duration, its unique function is the quantitative measurement of intensity, which is needed for the MVU calculation.

What is considered the upper limit of normal for uterine resting tone as measured by an Intrauterine Pressure Catheter (IUPC) in a laboring patient?

Answer: 25 mm Hg

Normal uterine resting tone during labor, measured by an IUPC, typically ranges from 5 to 25 mm Hg between contractions. A resting tone consistently above 20-25 mm Hg is considered elevated or uterine hypertonus, which can impair uteroplacental blood flow and fetal oxygenation.