title: Mode of delivery has an independent impact on neonatal condition at birth.
abstract: OBJECTIVE
  Current intra-partum monitoring techniques are often criticized for their poor specificity, with their performance frequently evaluated using measures of the neonatal condition at birth as a surrogate marker for intra-partum fetal compromise. However, these measures may potentially be influenced by a multitude of other factors, including the mode of delivery itself. This study aimed to investigate the impact of mode of delivery on neonatal condition at birth.
  
  
  METHODS
  This prospective observational study, undertaken at a tertiary referral maternity unit in London, UK, included 604 'low risk' women recruited prior to delivery. Commonly assessed neonatal outcome variables (Apgar score at 1 and 5min, umbilical artery pH and base excess, neonatal unit admission, and a composite neonatal outcome score) were used to compare the condition at birth between babies born by different modes of delivery, using one-way ANOVA and chi-squared testing.
  
  
  RESULTS
  Infants born by instrumental delivery for presumed fetal compromise had the poorest condition at birth (mean composite score=1.20), whereas those born by Cesarean section for presumed fetal compromise had a better condition at birth (mean composite score=0.64) (p=<0.001). No difference in composite neonatal outcome scores was observed between babies born by instrumental delivery for a prolonged second stage (no evidence of compromise), and those born by Cesarean delivery for presumed fetal compromise.
  
  
  CONCLUSIONS
  Mode of delivery represents a potential confounding factor when using condition at birth as a surrogate marker of intra-partum fetal compromise. When evaluating the efficacy of intra-partum monitoring techniques, the isolated use of Apgar scores, umbilical artery acidosis and neonatal unit admission should be discouraged.
authors.affiliation: Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, Du Cane Road, London W12 0HS, UK; Institute for Reproductive and Developmental Biology, Imperial College London, London W12 0HS, UK; Mater Research Institute/University of Queensland, Aubigny Place, Raymond Terrace, South Brisbane 4101, QLD, Australia.
authors.forename: Tomas
authors.initials: T
authors.lastname: Prior
authors.affiliation: Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, Du Cane Road, London W12 0HS, UK; Institute for Reproductive and Developmental Biology, Imperial College London, London W12 0HS, UK; Mater Research Institute/University of Queensland, Aubigny Place, Raymond Terrace, South Brisbane 4101, QLD, Australia. Electronic address: sailesh.kumar@mater.uq.edu.au.
authors.forename: Sailesh
authors.initials: S
authors.lastname: Kumar
mesh_terms: D000137:Acid-Base Imbalance; D001034:Apgar Score; D002585:Cesarean Section; D004420:Dystocia / Q000628:therapy*; D005113:Extraction, Obstetrical; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005316:Fetal Distress / Q000150:complications / Q000628:therapy*; D005323:Fetal Monitoring; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D015931:Intensive Care, Neonatal; D007743:Labor, Obstetric; D011247:Pregnancy; D011446:Prospective Studies
keywords: Acidosis; Apgar score; Fetal distress; Nonreassuring fetal status