title: Low Apgar scores at 5 minutes in a low risk population: maternal and obstetrical factors and postnatal outcome.
abstract: OBJECTIVE
  To evaluate the association between Apgar scores of less than seven at five minutes (AS5min < 7) and antenatal factors and postnatal outcomes.
  
  
  METHODS
  A retrospective cohort and case-control study of 27,252 consecutive term newborns in a low risk obstetrical population between January 2003 and December 2010. Maternal and infant databases were reviewed from all cases with AS5min < 7 (n = 121; 0.4%) and 363 cases with AS5min > 7 at 5 minutes who were randomly selected by a computer program. The main outcomes were neonatal death, newborn respiratory distress, need for orotracheal intubation and neonatal intensive care unit (NICU), and hypoxic-ischemic-encephalopathy.
  
  
  RESULTS
  After multiple regression analysis, repeated late decelerations on cardiotocography (OR: 2.4; 95% CI: 1.4-4.1) and prolonged second stage of labor (OR: 3.3; 95% CI: 1.3-8.3) were associated with AS5min < 7, as well as neonatal respiratory distress (OR: 3.0; 95% CI: 1.3-6.9), orotracheal intubation (OR: 2.5; 95% CI: 1.2-4.8), need for NICU (OR: 9.5; 95% CI: 6.7-16.8), and hypoxic-ischemic-encephalopathy (OR: 14.1; 95% CI: 3.6-54.7). No other antenatal factors were associated with AS5min < 7 (p > 0.05).
  
  
  CONCLUSIONS
  Repeated late decelerations and prolonged second stage of labor in the low-risk population are predictors of AS5min < 7, a situation associated with increased risk of neonatal respiratory distress, need for mechanical ventilatory support and NICU, and hypoxic-ischemic-encephalopathy.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital, Medical School, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Eugenia Maria Assunção
authors.initials: EM
authors.lastname: Salustiano
authors.forename: Juliana Alvares Duarte Bonini
authors.initials: JA
authors.lastname: Campos
authors.forename: Silvia Maria
authors.initials: SM
authors.lastname: Ibidi
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ruano
authors.forename: Marcelo
authors.initials: M
authors.lastname: Zugaib
mesh_terms: D000293:Adolescent; D000328:Adult; D001034:Apgar Score; D001938:Brazil / Q000453:epidemiology; D002547:Cerebral Palsy / Q000175:diagnosis / Q000209:etiology; D005260:Female; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis* / Q000209:etiology; D007226:Infant Mortality; D007231:Infant, Newborn; D007748:Labor Stage, Second; D008423:Maternal Age; D011247:Pregnancy; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis* / Q000209:etiology; D012189:Retrospective Studies; D018570:Risk Assessment; D047929:Term Birth / Q000502:physiology; D055815:Young Adult