title: The association between influenza vaccine in pregnancy and adverse neonatal outcomes.
abstract: OBJECTIVE
  To determine whether neonatal outcomes differ between women vaccinated during pregnancy and those not vaccinated.
  
  
  METHODS
  Self-reported history of receipt of influenza vaccination during pregnancy was collected from women at the time of admission for obstetrical delivery at the IWK Health Centre in Halifax, Nova Scotia, beginning in April 2006. The cohort for this study included women who delivered a singleton infant prior to November 2009, reflecting the pre-pandemic H1N1 vaccination period. Neonatal outcomes were compared using logistic regression between vaccinated and non-vaccinated women.
  
  
  RESULTS
  Overall, 1957 of 9781 women (20%) included in the cohort received influenza vaccine during their pregnancy. The adjusted odds ratio and 95% confidence interval for a small for gestational age infant (lowest 10th percentile birth weight for gestational age and sex) was 0.80 (95% CI 0.65 to 0.95) for vaccinated women relative to non-vaccinated women. The adjusted odds ratio for a low birth weight infant was 0.74 (95% CI 0.58 to 0.95). Rates of preterm birth and a composite indicator of adverse neonatal outcomes were lower among vaccinated women, but were not statistically significant. The effects of maternal vaccination on neonatal outcomes did not differ between high- and low-risk women.
  
  
  CONCLUSIONS
  As evidence continues to mount in support of improved neonatal outcomes associated with receiving influenza vaccination during pregnancy, enhanced public health measures are necessary to encourage pregnant women to receive the influenza vaccine.
authors.affiliation: Canadian Center for Vaccinology, Halifax NS; Department of Obstetrics and Gynaecology, Dalhousie University, Halifax NS; Perinatal Epidemiology Research Unit, IWK Health Centre, Halifax NS; Department of Pediatrics, Dalhousie University, Halifax NS.
authors.forename: Linda
authors.initials: L
authors.lastname: Dodds
authors.affiliation: Canadian Center for Vaccinology, Halifax NS; Department of Pediatrics, Dalhousie University, Halifax NS.
authors.forename: Noni
authors.initials: N
authors.lastname: MacDonald
authors.affiliation: Canadian Center for Vaccinology, Halifax NS; Department of Pediatrics, Dalhousie University, Halifax NS.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Scott
authors.affiliation: Perinatal Epidemiology Research Unit, IWK Health Centre, Halifax NS.
authors.forename: Anne
authors.initials: A
authors.lastname: Spencer
authors.affiliation: Canadian Center for Vaccinology, Halifax NS; Department of Obstetrics and Gynaecology, Dalhousie University, Halifax NS.
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Allen
authors.affiliation: Canadian Center for Vaccinology, Halifax NS; Department of Pediatrics, Dalhousie University, Halifax NS; Department of Medicine, Dalhousie University, Halifax NS.
authors.forename: Shelly
authors.initials: S
authors.lastname: McNeil
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000009:adverse effects*; D009674:Nova Scotia; D016017:Odds Ratio; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000453:epidemiology
chemical_list: D007252:Influenza Vaccines