title: The perinatal effects of delayed childbearing.
abstract: OBJECTIVE
  To determine if the rates of pregnancy complications, preterm birth, small for gestational age, perinatal mortality, and serious neonatal morbidity are higher among mothers aged 35-39 years or 40 years or older, compared with mothers 20-24 years.
  
  
  METHODS
  We performed a population-based study of all women in Nova Scotia, Canada, who delivered a singleton fetus between 1988 and 2002 (N = 157,445). Family income of women who delivered between 1988 and 1995 was obtained through a confidential linkage with tax records (n = 76,300). The primary outcome was perinatal death (excluding congenital anomalies) or serious neonatal morbidity. Analysis was based on logistic models.
  
  
  RESULTS
  Older women were more likely to be married, affluent, weigh 70 kg or more, attend prenatal classes, and have a bad obstetric history but less likely to be nulliparous and to smoke. They were more likely to have hypertension, diabetes mellitus, placental abruption, or placenta previa. Preterm birth and small-for-gestational age rates were also higher; compared with women aged 20-24 years, adjusted rate ratios for preterm birth among women aged 35-39 years and 40 years or older were 1.61 (95% confidence interval [CI] 1.42-1.82; P < .001) and 1.80 (95% CI 1.37-2.36; P < .001), respectively. Adjusted rate ratios for perinatal mortality/morbidity were 1.46 (95% CI 1.11-1.92; P = .007) among women 35-39 years and 1.95 (95% CI 1.13-3.35; P = .02) among women 40 years or older. Perinatal mortality rates were low at all ages, especially in recent years.
  
  
  CONCLUSIONS
  Older maternal age is associated with relatively higher risks of perinatal mortality/morbidity, although the absolute rate of such outcomes is low.
authors.affiliation: Perinatal Epidemiology Research Unit, Departments of Obstetrics and Gynaecology and Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada. ksjoseph@dal.ca
authors.forename: K S
authors.initials: KS
authors.lastname: Joseph
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Allen
authors.forename: Linda
authors.initials: L
authors.lastname: Dodds
authors.forename: Linda Ann
authors.initials: LA
authors.lastname: Turner
authors.forename: Heather
authors.initials: H
authors.lastname: Scott
authors.forename: Robert
authors.initials: R
authors.lastname: Liston
mesh_terms: D000328:Adult; D005193:Family Planning Services; D005260:Female; D006801:Humans; D007182:Income; D007226:Infant Mortality; D007231:Infant, Newborn; D016015:Logistic Models; D008423:Maternal Age; D009674:Nova Scotia; D007752:Obstetric Labor, Premature / Q000453:epidemiology; D010298:Parity; D011247:Pregnancy; D011248:Pregnancy Complications; D011256:Pregnancy Outcome; D011295:Prenatal Care; D012907:Smoking