Intrapartum PRSA: a new method to predict fetal acidosis?-a case-control study

Area of Science:

• Perinatal medicine
• Fetal monitoring
• Signal processing in healthcare

Background:

• Fetal cardiotocography (CTG) is crucial for monitoring fetal well-being.
• Assessing fetal autonomic nervous system (ANS) function aids in predicting adverse outcomes.
• Quantifying fetal heart rate variability provides insights into fetal health.

Purpose of the Study:

• To evaluate the efficacy of the phase-rectified signal averaging method (PRSA) in predicting perinatal acidosis.
• To determine if average deceleration capacity (ADC) calculated via PRSA can identify fetuses at risk.
• To assess the utility of PRSA as an adjunct tool for intrapartum fetal monitoring.

Main Methods:

• A case-control study analyzed intrapartum CTG tracings from a 7-year period.
• Cases were neonates with umbilical arterial blood pH ≤ 7.10; controls had pH ≥ 7.25.
• Average deceleration capacity (ADC) and short-term variability (STV) were calculated in the final 30-60 minutes before delivery.

Main Results:

• 227 CTG recordings met inclusion criteria.
• ADC was significantly higher in fetuses with acidemia (4.85 bpm ± 3.0) compared to controls (3.36 bpm ± 2.2).
• The area under the ROC curve for ADC was 0.659, indicating predictive value for acidosis.

Conclusions:

• PRSA-derived ADC is a valuable tool for predicting acute fetal acidosis during delivery.
• This method enhances the assessment of fetal autonomic nervous system status.
• ADC offers an additional layer of information for intrapartum fetal surveillance.