title: Influence of gestational age and time of day in baseline and heart rate variation of fetuses.
abstract: BACKGROUND
  Fetal electrocardiography (FECG) places electrodes on the maternal abdomen to convert the fetal electrocardiosignals into fetal heart rate (FHR), improving the accuracy and comfort of pregnant woman. At the same time, FECG simplifies the procedure of long term monitoring in the perinatal period.
  
  
  OBJECTIVE
  Investigating the influence of gestational age and time of day on FHR features to distinguish between non-stress test (NST) normal fetuses and NST suspicious fetuses.
  
  
  METHODS
  A novel method of FHR baseline estimation was presented; then baseline value and fetal heart rate variation (FHRV) were analyzed in the time domain using FHR signals recorded from 52 fetuses.
  
  
  RESULTS
  Baseline values in 1:00, 2:00, 4:00, 5:00 and heart rate variation (HRV) distribution showed a significant difference (p< 0.05) between NST normal fetuses and NST suspicious fetuses.
  
  
  CONCLUSIONS
  The results suggest that NST normal and suspicious fetuses had same outcome and different FHR features. Accurately distinguishing normal fetuses and suspicious fetuses is important for lowering the false positive rate and reducing unnecessary clinical intervention.
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China.
authors.forename: Guangfei
authors.initials: G
authors.lastname: Li
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China.
authors.forename: Song
authors.initials: S
authors.lastname: Zhang
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.affiliation: Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China.
authors.forename: Shufang
authors.initials: S
authors.lastname: Li
authors.affiliation: Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Hao
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China.
authors.forename: Xuwen
authors.initials: X
authors.lastname: Li
authors.affiliation: Beijing Yes Medical Devices Co., Ltd., Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Beijing Aerospace ChangFeng Co., Ltd., Beijing, China.
authors.forename: Mingzhou
authors.initials: M
authors.lastname: Xu
mesh_terms: D000328:Adult; D004562:Electrocardiography; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D005333:Fetus; D005865:Gestational Age; D006340:Heart Rate, Fetal; D006801:Humans; D011247:Pregnancy; D013997:Time Factors
keywords: Fetal heart rate (FHR); baseline; gestational age (GA); heart rate variation (HRV)