Duration and frequency pattern of baseline fetal heart rate variability loss in non-category Ⅲ fetal heart rate monitoring
OU You-liang
ZHOU Yan-li
SHENG Chao
WU Yu-yu
DU Ping-ping
Abstract：Objective To investigate the duration and frequency patterns of baseline fetal heart rate(FHR)vari-ability loss in non-Category Ⅲ fetal heart rate monitoring.Methods A random selection of 2 000 pregnant women with regular antenatal care and hospital deliveries from January 2020 to May 2023,each carrying a singleton fetus,were includ-ed in the study.Participants were categorized into high-risk and low-risk groups based on the presence of high-risk factors.Starting from 28 weeks of gestation,daily fetal heart rate monitoring was conducted until delivery.The duration and frequency of baseline FHR variability loss were observed and recorded.Results In 28-40+6weeks of pregnancy,the median duration of baseline FHR variability loss was 5.45-12.40 seconds per episode in the low-risk group and 5.95-12.00 seconds per episode in the high-risk group.The median frequency was 2.00-3.00 episodes per 20 mi-nutes in the low-risk group and 2.00-3.00 episodes per 20 minutes in the high-risk group.Repeated measures ANO-VA indicated significant differences between groups in terms of time effect,group effect,and interaction effect for the du-ration and frequency of baseline FHR variability loss(P＜0.05).Within 12 hours before the baseline FHR variability loss event,the median(interquartile range)duration of baseline FHR variability loss was 12.40(11.80,13.50)seconds per episode in the low-risk group and 12.70(11.80,13.50)seconds per episode in the high-risk group.The median(in-terquartile range)frequency of baseline FHR variability loss in both groups was 4.00(3.00,5.00)episodes per 20 mi-nutes.Repeated measures ANOVA showed a significant time effect for the duration of baseline FHR variability loss be-tween the two groups(P＜0.05).Conclusion The loss of baseline FHR variability in non-category Ⅲ fetal heart rate monitoring reflects physiological immaturity of fetal heart rate and is influenced by clinical monitoring conditions.Longer durations of variability loss and higher frequencies are associated with increased fetal risk.A duration of ≥10 seconds per episode and frequency of ≥3 episodes per 20 minutes indicate significant baseline FHR variability loss and require timely intervention.
Keywords：non-category Ⅲ fetal heart rate monitoringbaseline fetal heart rate variability lossdurationfre-quencybaseline fetal heart rate variability loss event
Publication Date：2024-08-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 1004-1010 )