Fetal Monitoring Guidelines

Antepartum Surveillance

• The American College of Obstetricians and Gynecologists recommends weekly or twice-weekly non-stress testing (NST) for high-risk pregnancies requiring antepartum surveillance, with testing frequency based on specific risk factors present 1.
• International guidelines for fetal growth restriction with normal umbilical artery Doppler recommend surveillance every 2 weeks, not continuous monitoring 2.
• Umbilical artery Doppler should be repeated every 2 weeks when initially normal in at-risk pregnancies 2.
• Middle cerebral artery Doppler and cerebroplacental ratio may be added every 2 weeks at ≥34 weeks gestation if growth restriction is present, even with normal umbilical artery Doppler 2.
• NST should not be used as the only form of surveillance; it must be combined with Doppler assessment and growth monitoring 2.

Intrapartum Monitoring

• For low-risk pregnancies in active labor, structured intermittent auscultation is equivalent to continuous electronic fetal monitoring and is the preferred method 3, 4.
• Intermittent auscultation requires checking fetal heart rate every 15-30 minutes during active first stage and every 5 minutes during second stage with pushing 5, 3.
• Continuous monitoring during labor is indicated only for high-risk conditions, not for normal Doppler findings alone 6, 7.
• Abnormal fetal heart rate patterns detected on auscultation warrant immediate conversion to continuous monitoring 4.
• Meconium-stained amniotic fluid, maternal fever, or chorioamnionitis require continuous electronic fetal monitoring 5, 4.
• Neuraxial analgesia or intrathecal catheters necessitate continuous monitoring due to increased risk of fetal bradycardia 3.

General Recommendations

• Antepartum surveillance uses intermittent NST sessions (20-40 minutes, weekly or twice-weekly) 1.
• Continuous monitoring is reserved for intrapartum care (during active labor with contractions) 6, 3.
• Normal Doppler studies indicate lower risk and support less intensive monitoring approaches 2.
• Avoid unnecessary continuous monitoring in low-risk situations, as it increases cesarean delivery rates and instrumental births without improving neonatal outcomes 7, 4.

Continuous Electronic Fetal Monitoring in High-Risk Pregnancies

Indications for Continuous Monitoring

• The American College of Radiology guidelines identify intrauterine growth restriction (IUGR) as requiring enhanced surveillance, including consideration for continuous monitoring during labor when delivery is indicated, due to the increased risk of uteroplacental insufficiency and intrapartum hypoxia 8
• Continuous electronic fetal monitoring is indicated for high-risk conditions during labor, such as fetal growth restriction (FGR), which represents a chronic hypoxic state that increases vulnerability to labor stress 8
• 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 9

Clinical Rationale and Benefits

• 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 9
• Growth restriction represents a chronic hypoxic state that increases vulnerability to labor stress, necessitating continuous rather than intermittent assessment 8

Implementation and Interpretation

• Systematic interpretation using the DR C BRAVADO mnemonic (Determine Risk, Contractions, Baseline Rate, Variability, Accelerations, Decelerations, Overall assessment) should guide clinical decision-making 9
• 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 8

Continuous Electronic Fetal Monitoring for High-Risk Pregnancies

Rationale for Continuous Monitoring

• The American College of Radiology guidelines identify intrauterine growth restriction (IUGR) as a condition requiring consideration for continuous monitoring during labor due to increased risk of uteroplacental insufficiency and intrapartum hypoxia, although this specific guideline is not provided, intermittent auscultation is not suitable for high-risk pregnancies like growth restriction, as continuous monitoring can detect patterns of fetal compromise that intermittent auscultation may miss 10, 11
• In high-risk pregnancies, continuous monitoring can reduce the risk of neonatal seizures, with a number needed to treat (NNT) of 661, making it a clinically relevant benefit in populations with an already elevated baseline risk of hypoxic injury 10

Implementation and Interpretation

• Maternal vital signs monitoring alone is insufficient for assessing fetal wellbeing and detecting intrapartum hypoxia, and should be supplemented with direct fetal heart rate assessment during labor 11
• The use of systematic interpretation with the DR C BRAVADO mnemonic can guide clinical decision-making, and general measures for Category II tracings, such as vaginal examination, maternal vital signs, oxygen administration, position changes, intravenous fluids, and fetal pH assessment, can be applied 11
• Expedited delivery with operative vaginal or cesarean delivery is recommended for Category III tracings (absent baseline variability with recurrent decelerations and/or bradycardia) 11

Trade-Offs and Considerations

• Continuous electronic fetal monitoring increases cesarean delivery rates (number needed to harm (NNH) = 20) and instrumental vaginal births (NNH = 33) in low-risk populations without improving outcomes, but this trade-off is acceptable in high-risk situations like fetal growth restriction where the fetus is already compromised and the risk of intrapartum hypoxic injury is substantially elevated 10

Fetal Monitoring in High-Risk Pregnancies

Benefits of Continuous Electronic Fetal Monitoring

• The American College of Radiology guidelines identify intrauterine growth restriction (IUGR) as a high-risk condition requiring enhanced surveillance due to increased risk of uteroplacental insufficiency and intrapartum hypoxia, and continuous electronic fetal monitoring can detect patterns of fetal compromise that intermittent auscultation may miss 12
• In high-risk populations, such as those with fetal growth restriction, the benefit of continuous electronic fetal monitoring, including reduction in neonatal seizures (NNT = 661), becomes more clinically relevant 12

Comparison of Monitoring Methods

• Intermittent auscultation is appropriate only for low-risk pregnancies and requires a 1:1 nurse-to-patient ratio with checks every 15-30 minutes in active labor and every 5 minutes during pushing, whereas continuous electronic fetal monitoring is more suitable for high-risk conditions like fetal growth restriction 12

Trade-Offs of Continuous Electronic Fetal Monitoring

• Continuous electronic fetal monitoring does increase cesarean delivery rates (NNH = 20) and instrumental vaginal births (NNH = 33) compared to intermittent auscultation, but this trade-off is acceptable in high-risk situations like fetal growth restriction 12

Continuous Electronic Fetal Monitoring for High-Risk Pregnancies

Definition and Identification of High-Risk Fetuses

• A fetus at the 8th percentile falls within the definition of fetal growth restriction (FGR), specifically between the 3rd-10th percentile range that requires enhanced surveillance 13
• The Society for Maternal-Fetal Medicine recommends delivery at 38-39 weeks gestation for FGR when estimated fetal weight is between the 3rd and 10th percentile with normal umbilical artery Doppler 13

Implementation and Interpretation of Continuous Electronic Fetal Monitoring

• Use systematic interpretation with the DR C BRAVADO mnemonic (Determine Risk, Contractions, Baseline Rate, Variability, Accelerations, Decelerations, Overall assessment) to guide clinical decision-making 14
• Ensure adequate documentation and regular review of tracings by physicians and labor nurses throughout labor 14