title: Post-term pregnancy is an independent risk factor for neonatal morbidity even in low-risk singleton pregnancies.
abstract: OBJECTIVE
  To determine the independent association of post-term pregnancy with neonatal outcome in low-risk newborns.
  
  
  METHODS
  Retrospective cohort.
  
  
  METHODS
  Tertiary university-affiliated medical centre.
  
  
  METHODS
  All newborns of low-risk singleton pregnancies born at 39+0 to 44+0 weeks' gestation over a 5-year period.
  
  
  METHODS
  multiple gestation, maternal hypertensive disorder, diabetes or cholestasis, placental abruption or intrapartum fever (>38°C), small for gestational age (<10th centile) and major congenital or chromosomal anomalies.
  
  
  METHODS
  None.
  
  
  METHODS
  Admission to the neonatal intensive care unit (NICU), hospital length of stay, 5-min Apgar score, birth trauma, respiratory, neurological, metabolic and infectious morbidities and neonatal mortality. The adverse outcome rate was compared among three groups based on gestational age at birth: post-term (≥42+0 weeks), late term (41+0 to 41+6 weeks) and full term (39+0 to 40+6 weeks).
  
  
  RESULTS
  Of the 23 524 eligible neonates, 747 (3.2%) were born post-term, 4632 (19.7%) late term and 18 145 (77.1%) full term. Women in the post-term group versus the late-term group had a significantly higher rate of caesarean section (8.9% vs 5.6%, p<0.001) and operative vaginal delivery (9.6% vs 7.4%, p=0.024). Post-term pregnancy versus full-term pregnancy was associated with an increased risk of NICU admission (OR 2.0, 95% CI 1.4 to 2.8), respiratory morbidity (OR 2.2, 95% CI 1.3 to 3.8) and infectious morbidity (OR 1.88, 95% CI 1.32 to 2.69). Post-term pregnancy versus late-term pregnancy was similarly associated with an increased risk of NICU admission (OR 2.0, 95% CI 1.4 to 2.9), respiratory morbidity (OR 2.7, 95% CI 1.5 to 5.0) and infectious morbidity (OR 1.8, 95% CI 1.2 to 2.7) and with hypoglycaemia (OR 2.6, 95% CI 1.2 to 5.4). Post-term delivery was not associated with neonatal mortality.
  
  
  CONCLUSIONS
  Post-term pregnancy is an independent risk factor for neonatal morbidity even in low-risk singleton pregnancies.
authors.affiliation: Department of Neonatology, The Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Israel.|Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Nehama
authors.initials: N
authors.lastname: Linder
authors.affiliation: Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.|Departments of Obstetrics and Gynecology, The Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: Liran
authors.initials: L
authors.lastname: Hiersch
authors.affiliation: Department of Neonatology, The Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: Elana
authors.initials: E
authors.lastname: Fridman
authors.affiliation: Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.|Neonatal Intensive Care Unit, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
authors.forename: Gil
authors.initials: G
authors.lastname: Klinger
authors.affiliation: Department of Neonatology, The Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lubin
authors.affiliation: Department of Neonatology, The Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: Franck
authors.initials: F
authors.lastname: Kouadio
authors.affiliation: Departments of Obstetrics and Gynecology, The Helen Schneider Hospital for Women, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: Nir
authors.initials: N
authors.lastname: Melamed
mesh_terms: D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology*; D007233:Infant, Postmature / Q000502:physiology*; D007751:Labor, Induced / Q000706:statistics & numerical data*; D054238:Perinatal Mortality; D011247:Pregnancy; D011273:Pregnancy, Prolonged / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Neonatal complications; post-term; singleton