title: Relationship Between Interpregnancy Interval and Adverse Perinatal and Neonatal Outcomes in Northern Alberta.
abstract: BACKGROUND
  Birth outcomes are known to be associated with birth spacing, but there are population differences. The purpose of this study was to examine the association between interpregnancy intervals and perinatal and neonatal outcomes in a Canadian population during the era of mandatory folate fortification of food.
  
  
  METHODS
  We conducted a study of 46 243 women who had two consecutive singleton births in northern Alberta between 1999 and 2007, using a linked provincial dataset. Perinatal outcomes of interest were preterm birth, low birth weight (LBW), small for gestational age, and perinatal death. Neonatal outcomes were low Apgar score, low arterial blood gas pH, need for neonatal resuscitation or admission to NICU, and neonatal death. Multivariable logistic regression was used to control for maternal demographic and obstetrical characteristics.
  
  
  RESULTS
  The risk of preterm birth was increased for multiple interpregnancy intervals: for an interval of 0 to 5 months, the adjusted odds ratio (aOR) was 1.37 (95% CI 1.18 to 1.59), for 6 to 11 months the aOR was 1.18 (95% CI 1.04 to 1.34), for 24 to 35 months the aOR was 1.16 (95% CI 1.02 to 1.31), and for 36+ months the aOR was 1.36 (95% CI 1.20 to 1.53), compared with the reference interval of 12 to 17 months. The risk of LBW was increased with interpregnancy intervals of 0 to 5 months (aOR 1.48; 95% CI 1.23 to 1.80), 6 to 11 months (aOR 1.21; 95% CI 1.03 to 1.42), 24 to 35 months (aOR 1.21; 95% CI 1.03 to 1.41) and 36+ months (aOR 1.48; 95% CI 1.27 to 1.73). The risk of SGA was increased with intervals 0 to 5 months (aOR 1.29; 95% CI 1.09 to 1.52), 24 to 35 months (aOR 1.15; 95% CI 1.01 to 1.31), and 36+ months (aOR 1.26; 95% CI 1.11 to 1.44). The risk of perinatal death was increased with an interval of 36+ months (aOR 1.60; 95% CI 1.06 to 2.43). Similar associations were also observed for neonatal outcomes.
  
  
  CONCLUSIONS
  This study suggests that both short and long interpregnancy intervals are associated with adverse perinatal and neonatal outcomes, and it provides risk estimates for a Canadian population in the era of folate fortification of food.
authors.affiliation: Department of Obstetrics and Gynecology, University of Ottawa and the Ottawa Hospital Research Institute, Ottawa ON.
authors.forename: Innie
authors.initials: I
authors.lastname: Chen
authors.affiliation: School of Public Health, University of Alberta, Edmonton AB.
authors.forename: Gian S
authors.initials: GS
authors.lastname: Jhangri
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Alberta, Edmonton AB.
authors.forename: Michelle
authors.initials: M
authors.lastname: Lacasse
authors.affiliation: Neonatal Division, Department of Pediatrics, University of Alberta, Edmonton AB.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Alberta, Edmonton AB.
authors.forename: Sujata
authors.initials: S
authors.lastname: Chandra
mesh_terms: D000328:Adult; D000416:Alberta / Q000453:epidemiology; D001034:Apgar Score; D001721:Birth Intervals; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D015931:Intensive Care, Neonatal / Q000706:statistics & numerical data; D066087:Perinatal Death; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012151:Resuscitation / Q000706:statistics & numerical data; D055815:Young Adult
keywords: birth spacing; interpregnancy interval; low birth weight; neonatal death; perinatal death; perinatal outcomes; preterm birth; small for gestational age