title: Fetal heart rate baselines in twins. Interobserver agreement in antepartum estimation.
abstract: OBJECTIVE
  To assess interobserver agreement in antepartum estimation of fetal heart rate (FHR) baselines in twins.
  
  
  METHODS
  Two residents and one specialist in obstetrics and gynecology, all with special interest in FHR monitoring, independently estimated baselines in 162 consecutive antepartum FHR tracings recorded in 24 twins. Tracings were obtained with a dual-channel fetal monitor for the simultaneous recording of both twins' heart rates. Baselines were estimated, as single values corresponding to the mean of the lowest stable FHR segment, in the absence of fetal movements and uterine contractions, within physiologic limits (110-150 beats per minute [bpm]). If these criteria were not met, the possibility of persistent bradycardia or tachycardia was considered, and if this was confirmed in a tracing with at least 40 minutes, a baseline < 110 or > 150 bpm was chosen. Interobserver agreement was assessed by the proportions of agreement (PA), kappa statistic (K) and intraclass correlation coefficient (ICCC), with 95% confidence intervals (CIs).
  
  
  RESULTS
  Interobserver agreement was excellent, with a PA of 0.90 (95% CI: 0.89-0.91), K of 0.88 (95% CI: 0.84-0.92) and ICCC of 0.91 (95% CI: 0.88-0.94).
  
  
  CONCLUSIONS
  Interobserver agreement in antepartum estimation of fetal heart rate baselines in twins was excellent with the baseline concept used in this study.
authors.affiliation: Department of Gynecology and Obstetrics, Faculdade de Medicina do Porto, Portugal. Jbernardes@mail.telepac.pt
authors.forename: J
authors.initials: J
authors.lastname: Bernardes
authors.forename: A
authors.initials: A
authors.lastname: Costa-Pereira
authors.forename: L
authors.initials: L
authors.lastname: Calejo
authors.forename: D
authors.initials: D
authors.lastname: Ayres-de-Campos
authors.forename: B
authors.initials: B
authors.lastname: Patrício
authors.forename: L
authors.initials: L
authors.lastname: Pereira-Leite
mesh_terms: D000328:Adult; D005260:Female; D005333:Fetus / Q000502:physiology*; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D007396:Internship and Residency; D015588:Observer Variation; D009774:Obstetrics; D011247:Pregnancy; D011295:Prenatal Care; D011361:Professional Competence; D014427:Twins