Morbidity and mortality of twins and triplets compared to singleton infants delivered between 26-34 weeks gestation in the United States.

Objective: To describe in-hospital morbidities and mortality among twins and triplets delivered at ≥26 to ≤34 weeks gestational age (GA) while controlling for prematurity and growth restriction.

Study Design: Retrospective analysis of inborn infants discharged from a neonatal intensive care unit (NICU) managed by the Pediatrix Medical Group between 2010 and 2018.

Result: Among 247 437 infants included, 27.4% were multiples. Adjusted for GA and other factors typically known prior to delivery, in-hospital morbidities varied by plurality and generally were more common in singletons. The odds of death prior to discharge were less for twins at 0.74 (95% CI: 0.67-0.83) and triplets at 0.69 (95% CI: 0.51-0.92) compared to singletons.

Conclusion: Singletons experience greater morbidity and mortality compared to twins and triplets born ≥26 weeks to ≤34 weeks GA, except PDA requiring procedural intervention, ROP requiring treatment, and longer length of stay.