Open Collections

Temporal trends in neonatal mortality and morbidity following spontaneous and clinician-initiated preterm birth in Canada and the United States

University of British Columbia

Preterm birth (PTB; <37 weeks’ gestation) is the leading cause of neonatal mortality and morbidity. After a decade of increase, the PTB rate has declined in the United States since 2006. In Canada, PTB rates have remained stable, despite the rise in clinician-initiated deliveries at late preterm (34-36 weeks) since 2006. I examined temporal trends in the rates of spontaneous and clinician-initiated singleton PTB and assessed concomitant changes in neonatal mortality and severe morbidity. I conducted two retrospective population-based studies included singleton births (24-45 weeks) in Washington State (WA), U.S.A., 2004-2013, using birth certificate data linked to hospitalization records (N=754,763), and in Canada (excluding Quebec), 2009/2010-2015/2016, using national data on all hospital births (N=1,887,362). Primary outcomes were neonatal mortality and a composite outcome including death and/or severe neonatal morbidity (identified by diagnostic codes; definitions varied in both studies). Statistical significance was assessed using the Cochran-Armitage test for trend. Logistic regression yielded adjusted odds ratios (AOR) per 1-year change and 95% confidence intervals (CI). The singleton PTB rate in WA declined from 7.3% in 2004-2006 to 7.0% in 2011-2013 (n=52,014), predominantly due to declines in spontaneous labour and PPROM. The proportion of clinician-initiated PTBs increased from 37.7% to 40.7% in WA (p=0.004). Similarly, clinician-initiated deliveries increased from 31.0% in 2009/2010 to 37.9% in 2015/2016 in Canada (p<0.001). The corresponding decrease in spontaneous PTBs resulted in a stable PTB rate (6.2%; n=117,114) across Canada. Overall, neonatal mortality remained unchanged; 1.3% in WA and 1.1% in Canada. In subgroup analysis, neonatal mortality decreased at 32-33 weeks (AOR:0.85, CI:0.74-0.97) and increased at 34-36 weeks (AOR:1.10, CI:1.01-1.20) following clinician-initiated delivery in WA; mortality decreased at 28-33 weeks (AOR:0.91, CI:0.86-0.97) after spontaneous PTB in Canada. The composite outcome of neonatal mortality/severe morbidity increased from 7.9% to 11.9% (AOR:1.06, CI:1.05-1.08) in WA, mainly at 34-36 weeks. Neonatal mortality/severe morbidity decreased from 12.7% to 12.2% (AOR:0.98, CI:0.97-0.99) in Canada, particularly in clinician-initiated late PTB. The endured increase in clinician-initiated PTB was not associated with increased adverse neonatal outcomes in Canada. The increase in adverse neonatal health outcomes in Washington State, particularly at late preterm, warrant further investigation.

Text

2018-12-12

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/68054

Reproductive and Developmental Sciences

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/