title: The impact of advanced maternal age and parity on obstetric and perinatal outcomes in singleton gestations.
abstract: OBJECTIVE
  To investigate the effect of advanced maternal age (AMA) separately in nulliparous and multiparous women on obstetric and perinatal outcomes in singleton gestations.
  
  
  METHODS
  A historical cohort study on data from 6,619 singleton pregnancies between 2004 and May 2007 was performed. AMA was defined as 35 years and older. Obstetric and perinatal outcomes in AMA versus women younger than 35 years (non-AMA) were compared for both nulli- and multiparae with Student's t-test and Chi-square test in univariate analysis. Multiple logistic regression analysis was performed to examine the independent effect of AMA.
  
  
  RESULTS
  Out of 6,619 singleton pregnancies, the frequency of nulliparity was 42.7 and 33.4% of the parturients were of AMA. Among nulliparous women, AMA was significantly associated with a higher frequency of caesarean section both before labour (OR 2.26 with 95% CI 1.74-2.94), in labour (OR 1.44 with 95% CI 1.07-1.93), and more instrumental vaginal deliveries (ORs 1.49 with 95% CI 1.13-1.96). Among multiparous women, AMA was only significantly associated with a higher caesarean section rate before labour (ORs 1.42, 95% CI 1.19-1.69). There were no significant differences between the two age groups in the prevalence of other adverse obstetric outcomes and adverse perinatal outcomes.
  
  
  CONCLUSIONS
  Operative delivery is increased in AMA, including caesarean sections, as well as instrumental vaginal deliveries in nulliparous women. In multiparous women, however, only the rate of caesarean section before labour was increased. AMA had no significant effect on other adverse obstetric and perinatal outcomes irrespective of parity.
authors.affiliation: Department of Gynaecology and Obstetrics, Oslo University Hospital, Rikshopitalet, 0023, Oslo, Norway. yun.wang@rikshospitalet.no
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.forename: Tom
authors.initials: T
authors.lastname: Tanbo
authors.forename: Thomas
authors.initials: T
authors.lastname: Abyholm
authors.forename: Tore
authors.initials: T
authors.lastname: Henriksen
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008423:Maternal Age; D009664:Norway / Q000453:epidemiology; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012189:Retrospective Studies