TY - JOUR AU - Mei-Dan, Elad; Shah, Jyotsna; Lee, Shoo; Shah, Prakesh S.; Murphy, Kellie E.; for the Canadian Neonatal Network Investigators TI - The Effect of Birth Order on Neonatal Morbidity and Mortality in Very Preterm Twins SN - 0735-1631 SN - 1098-8785 PY - 2017 JO - Am J Perinatol JF - American Journal of Perinatology LA - EN VL - 34 IS - 09 SP - 845 EP - 850 ET - 2017/02/23 DA - 2017/07/04 KW - birth order KW - neonatal morbidity KW - neonatal mortality KW - preterm twins AB - Objective  This retrospective cohort study examined the effect of birth order on neonatal morbidity and mortality in very preterm twins.Study Design Using 2005 to 2012 data from the Canadian Neonatal Network, very preterm twins born between 24 0/7 and 32 6/7 weeks of gestation were included. Odds of morbidity and mortality of second-born cotwins compared with first-born cotwins were examined by matched-pair analysis. Outcomes were neonatal death, severe brain injury (intraventricular hemorrhage grade 3 or 4 or persistent periventricular echogenicity), bronchopulmonary dysplasia, severe retinopathy of prematurity (ROP) (> stage 2), necrotizing enterocolitis (≥ stage 2), and respiratory distress syndrome (RDS). Multivariable analysis was performed adjusting for confounders.Result There were 6,636 twins (3,318 pairs) included with a mean gestational age (GA) of 28.9 weeks. A higher rate of small for GA occurred in second-born twins (10 vs. 6%). Mortality was significantly lower for second-born twins (4.3 vs. 5.3%; adjusted odds ratio: 0.75; 95% confidence interval [CI]: 0.59–0.95). RDS (66 vs. 60%; adjusted odds ratio: 1.40; 95% CI: 1.29–1.52) and severe retinopathy (9 vs. 7%; adjusted odds ratio: 1.46; 95% CI: 1.07–2.01) were significantly higher in second-born twins.Conclusion Thus, while second-born twins had reduced odds of mortality, they also had increased odds of RDS and ROP. PB - Thieme Medical Publishers DO - 10.1055/s-0037-1598255 UR - http://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0037-1598255 ER -