title: Advanced maternal age, short interpregnancy interval, and perinatal outcome.
abstract: OBJECTIVE
  The purpose of this study was to evaluate whether the association between short interpregnancy intervals and perinatal outcome varies with maternal age.
  
  
  METHODS
  We performed a retrospective cohort study among 263,142 Dutch women with second deliveries that occurred between 2000 and 2007. Outcome variables were preterm delivery (<37 weeks of gestation), low birthweight in term deliveries (<2500 g) and small-for-gestational age (<10th percentile for gestational age on the basis of sex- and parity-specific Dutch standards).
  
  
  RESULTS
  Short interpregnancy intervals (<6 months) was associated positively with preterm delivery and low birthweight, but not with being small for gestational age. The association of short interpregnancy interval with the risk of preterm delivery was weaker among older than younger women. There was no clear interaction between short interpregnancy interval and maternal age in relation to low birthweight or small for gestational age.
  
  
  CONCLUSIONS
  The results of this study indicate that the association of short interpregnancy interval with preterm delivery attenuates with increasing maternal age.
authors.affiliation: Department of Epidemiology, Care and Public Health Research Institute, Maastricht University Medical Center, the Netherlands.
authors.forename: Frederike J
authors.initials: FJ
authors.lastname: de Weger
authors.forename: Chantal W P M
authors.initials: CW
authors.lastname: Hukkelhoven
authors.forename: Jan
authors.initials: J
authors.lastname: Serroyen
authors.forename: Egbert R
authors.initials: ER
authors.lastname: te Velde
authors.forename: Luc J M
authors.initials: LJ
authors.lastname: Smits
mesh_terms: D000328:Adult; D001721:Birth Intervals; D001724:Birth Weight; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth; D012189:Retrospective Studies; D012307:Risk Factors