What is the best intrapartum surveillance method for a primigravida at 39 weeks gestation with a fetus at the 8th percentile?

Continuous Electronic Fetal Monitoring (Option C)

For a primigravida at 39 weeks with a fetus at the 8th percentile, continuous electronic fetal monitoring during labor is the appropriate intrapartum surveillance method because this represents a high-risk pregnancy requiring enhanced monitoring to detect fetal compromise. 1

Why This is High-Risk, Not Low-Risk

A fetus at the 8th percentile indicates fetal growth restriction (FGR), which fundamentally changes the risk stratification from low-risk to high-risk pregnancy. 2 This distinction is critical because:

• Growth restriction places the fetus at increased risk for uteroplacental insufficiency and intrapartum hypoxia, making continuous monitoring medically indicated rather than optional. 2
• The American College of Radiology guidelines specifically identify intrauterine growth restriction (IUGR) as requiring enhanced surveillance, including consideration for continuous monitoring during labor when delivery is indicated. 2
• Continuous electronic fetal monitoring is indicated for high-risk conditions during labor, and FGR definitively qualifies as such a condition. 1

Why Intermittent Auscultation is Inappropriate Here

While intermittent auscultation is the preferred method for low-risk pregnancies, this clinical scenario does not meet that criterion:

• Intermittent auscultation is equivalent to continuous monitoring only in healthy, uncomplicated, low-risk pregnancies—a category that explicitly excludes growth-restricted fetuses. 3
• The American Family Physician guidelines recommend intermittent auscultation for "healthy pregnancies in the active phase of labor" and "low-risk, uncomplicated pregnancies," neither of which applies to an 8th percentile fetus. 3
• Growth restriction represents a chronic hypoxic state that increases vulnerability to labor stress, necessitating continuous rather than intermittent assessment. 2

Why Maternal Vital Signs Alone are Inadequate

Maternal monitoring does not assess fetal well-being, which is the primary concern for detecting intrapartum hypoxia and preventing adverse neonatal outcomes in a growth-restricted fetus. 3

Clinical Rationale for Continuous Monitoring

The evidence supporting continuous monitoring in this high-risk scenario includes:

• In high-risk pregnancies, continuous electronic fetal monitoring can detect patterns of fetal compromise that intermittent auscultation may miss, particularly in fetuses already compromised by growth restriction. 2
• A 1993 randomized trial demonstrated that continuous EFM was associated with decreased perinatal mortality due to fetal hypoxia (0/746 vs 6/682; P = 0.03) compared to intermittent auscultation, though this came with increased surgical intervention rates. 4
• The only demonstrable benefit of continuous EFM—reduction in neonatal seizures—becomes more clinically relevant in high-risk populations where the baseline risk of hypoxic injury is elevated. 2, 3

Common Pitfall to Avoid

Do not apply low-risk labor management protocols to growth-restricted fetuses. The 8th percentile designation indicates this fetus has already demonstrated compromised growth, likely from placental insufficiency, making it fundamentally different from a normally grown fetus. 2 The increased cesarean delivery rate associated with continuous monitoring in low-risk populations is an acceptable trade-off when managing genuinely high-risk conditions like FGR. 2, 3

Implementation Requirements

• Continuous electronic fetal monitoring should be initiated upon admission to labor and delivery. 1
• Systematic interpretation using the DR C BRAVADO mnemonic (Determine Risk, Contractions, Baseline Rate, Variability, Accelerations, Decelerations, Overall assessment) should guide clinical decision-making. 2
• Be prepared for operative delivery if non-reassuring fetal heart rate patterns develop, as growth-restricted fetuses have limited physiologic reserve to tolerate labor stress. 2