Temporal Trends in Preterm Birth, Neonatal Mortality, and Neonatal Morbidity Following Spontaneous and Clinician-Initiated Delivery in Canada, 2009-2016

J Obstet Gynaecol Can. 2019 Dec;41(12):1742-1751.e6. doi: 10.1016/j.jogc.2019.02.151. Epub 2019 Jul 5.


Objective: Clinician-initiated deliveries at 34 to 36 weeks gestation have increased in Canada since 2006, but the impacts of clinician-initiated deliveries on the overall preterm birth (PTB) rate and concomitant changes in neonatal outcomes are unknown. This study examined gestational age-specific trends in spontaneous and clinician-initiated PTB and associated neonatal mortality and morbidity.

Methods: This population-based study included 1 880 444 singleton live births in Canada (excluding Québec) in 2009-2016, using hospitalization data from the Canadian Institute for Health Information. The primary outcomes were neonatal mortality and a composite outcome mortality and/or severe neonatal morbidity identified by International Statistical Classification of Diseases and Related Health Problems, 10th revision, Canada codes. Outcomes were stratified by spontaneous and clinician-initiated deliveries and gestational age categories. Logistic regression yielded adjusted odds ratios (aORs) per 1-year change and 95% confidence intervals (CIs) (Canadian Task Force Classification II-2).

Results: The PTB rate remained stable (6.2%) and the proportion of clinician-initiated PTBs increased from 31.0% to 37.9% (P < 0.001). Although overall neonatal mortality remained stable (1.1%), mortality declined among infants born spontaneously at 28 to 33 weeks gestation (aOR 0.92; 95% CI 0.87-0.97). The composite mortality and/or severe morbidity declined from 12.7% to 12.2% (aOR 0.98; 95% CI 0.97-0.99). Declines were observed in the rates of sepsis (aOR 0.96; 95% CI 0.95-0.98) and respiratory distress syndrome requiring ventilation (aOR 0.97; 95% CI 0.96-0.98), whereas rates of intraventricular hemorrhage increased (aOR 1.03; 95% CI 1.01-1.05).

Conclusion: With the increase in clinician-initiated deliveries, the stable rates of PTB and neonatal mortality and the decline in composite mortality and/or severe morbidity are encouraging findings. This study adds to clinical understanding of carefully timed and medically justified early interventions.

Keywords: Canada; Preterm birth; neonatal morbidity; neonatal mortality; trend.

MeSH terms

  • Adolescent
  • Adult
  • Canada / epidemiology
  • Delivery, Obstetric / adverse effects*
  • Delivery, Obstetric / statistics & numerical data
  • Delivery, Obstetric / trends
  • Female
  • Humans
  • Infant
  • Infant Mortality*
  • Infant, Newborn
  • Infant, Premature, Diseases / epidemiology*
  • Pregnancy
  • Premature Birth / epidemiology*
  • Premature Birth / etiology
  • Retrospective Studies
  • Young Adult