Computerized analysis of normal fetal heart rate pattern throughout gestation.

Area of Science:

• Perinatology
• Fetal Physiology
• Neonatal Monitoring

Background:

• Computerized cardiotocography (cCTG) is crucial for fetal well-being assessment.
• Understanding normal cCTG parameter evolution is essential for accurate interpretation.
• Previous studies have not comprehensively analyzed cCTG trends across a large cohort of healthy fetuses throughout gestation.

Purpose of the Study:

• To analyze the evolution of computerized cardiotocography (cCTG) parameters throughout gestation in a large archive of traces from healthy fetuses.
• To establish normal ranges for cCTG parameters from 25 to 42 weeks of gestation.
• To investigate the relationship between cCTG parameters and gestational age.

Main Methods:

• Cross-sectional study utilizing the first cCTG record from 4412 singleton fetuses with good pregnancy outcomes.
• Analysis of cCTG parameters including fetal heart rate (FHR) accelerations, short- and long-term variation, and episodes of high/low variation.
• Statistical investigation of parameter relationships with gestational age.

Main Results:

• FHR accelerations and variation generally increased with advancing gestation, while basal FHR decreased.
• Gestational age-related changes in FHR variation were less apparent at the lowest percentiles.
• Abrupt changes in FHR patterns were noted at 42 weeks, with increased decelerations and low variation episodes.

Conclusions:

• Normal FHR patterns are established early in gestation and follow a continuous trend.
• Significant changes in cCTG parameters occur around 42 weeks of gestation.
• Gestational age-related variations in FHR are less pronounced in fetuses with lower percentiles.