title: Interpreting category II fetal heart rate tracings: does meconium matter?
abstract: OBJECTIVE
  Category II fetal heart rate (FHR) tracings are considered indeterminate; thus, improved risk stratification of category II FHR tracings is needed. We estimated whether the presence of meconium increased the risk of adverse neonatal outcomes.
  
  
  METHODS
  This study was conducted within a prospective cohort of 5000 women with singleton pregnancies who were admitted in labor at term. Pregnancies with category II FHR in the 60 minutes before delivery were included. FHR data were extracted by trained nurses who were blinded to clinical outcome. The exposure was the presence of meconium. The primary outcome was a composite neonatal morbidity defined as ≥1 of the following: neonatal death, neurologic morbidity, respiratory morbidity, hypotension that required treatment, and sepsis. Secondary outcomes were nursery admission, cord pH, 5-minute Apgar score, and components of the composite. Logistic regression was used to adjust for confounders.
  
  
  RESULTS
  Of the 3257 women with category II FHR tracings, 693 women (21.3%) had meconium, and 2564 women (78.7%) did not. Meconium was associated with higher risk of the composite morbidity (adjusted odds ratio, 2.49; 95% confidence interval, 1.78-3.48) and increased risks of the secondary outcomes. The associations remained significant when infants with meconium aspiration syndrome were excluded. Thick meconium was associated significantly with the composite morbidity.
  
  
  CONCLUSIONS
  The presence of meconium is associated with an increased risk of neonatal morbidity in women with category II FHR pattern. This clinical factor may assist clinicians in managing category II FHR patterns in labor.
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO. Electronic address: Heather.A.Frey@gmail.com.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Frey
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO.
authors.forename: Methodius G
authors.initials: MG
authors.lastname: Tuuli
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Shanks
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO.
authors.forename: George A
authors.initials: GA
authors.lastname: Macones
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO.
authors.forename: Alison G
authors.initials: AG
authors.lastname: Cahill
mesh_terms: D000328:Adult; D000653:Amniotic Fluid; D015148:Cardiotocography; D005260:Female; D006340:Heart Rate, Fetal; D006801:Humans; D007022:Hypotension / Q000453:epidemiology; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology; D016015:Logistic Models; D008470:Meconium; D008471:Meconium Aspiration Syndrome / Q000453:epidemiology*; D015999:Multivariate Analysis; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D016017:Odds Ratio; D066087:Perinatal Death; D011247:Pregnancy; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D018805:Sepsis / Q000453:epidemiology; D055815:Young Adult
keywords: electronic fetal monitoring; fetal heart rate; meconium