On-line quantification of fetal heart rate variability

Area of Science:

• Biomedical Engineering
• Maternal-Fetal Medicine
• Signal Processing

Background:

• Fetal heart rate variability (FHRV) is crucial for assessing fetal well-being.
• Accurate on-line quantification of FHRV from fetal electrocardiography (FECG) remains a challenge.

Purpose of the Study:

• To present an on-line system for quantifying FHRV using FECG.
• To evaluate the accuracy and reliability of the developed system.
• To explore the potential of FHRV indices as markers for fetal status.

Main Methods:

• Development of a CMOS microprocessor system for on-line FHRV calculation.
• Calculation of interval index (II) for long-term variability and differential index (DI) for short-term variability.
• Validation of the system using simultaneous direct and abdominal FECG recordings.

Main Results:

• The system demonstrated good correlation between direct and abdominal FECG methods.
• Successful FHRV analysis ranged from 80-100% during weeks 20-27 and 35-term, with lower success (35-70%) between weeks 28-34.
• Both II and DI generally increased with gestational age, with DI showing stability after week 30.

Conclusions:

• The developed on-line FECG system reliably quantifies FHRV.
• The differential index (DI) shows potential as a novel marker for antepartum fetal status monitoring.
• FHRV analysis is feasible across different gestational periods, though success rates vary.