Objective There are no large studies evaluating pulmonary haemorrhage (PH) in premature infants. We sought to quantify the clinical characteristics, morbidities and mortality associated with early PH.

Design Data were abstracted from the Pediatrix Clinical Data Warehouse, a large de-identified data set. For incidence calculations, we included infants from 340 Pediatrix United States Neonatal Intensive Care Units from 2005 to 2014 without congenital anomalies. Infants <28 weeks’ gestation with PH within 7 days of birth were then matched with two controls for birth weight, gestational age, gender, antenatal steroid exposure, day of life 0 or 1 intubation and multiple gestation.

Results From 596 411 total infants, we identified 2799 with a diagnosis of PH. Peak incidence was 86.9 cases per 1000 admissions for neonates born at 24 weeks’ gestation. We then identified 1476 infants <28 weeks’ gestation with an early PH diagnosis at ≤7 days of age of which 1363 (92.3%) were successfully matched. Patients with early PH had significantly higher exposure to poractant alfa (35.4% vs 28%), diagnosis of shock (63.7% vs 51%) and grade IV intraventricular haemorrhage (20.8% vs 6%). Patients with PH also had significantly higher mortality rates at 7 days of age (40.6% vs 18.9%), 30 days of age (54% vs 28.8%) and prior to discharge (56.9% vs 33.7).

Conclusion In this large cohort of premature infants, we found PH to be common among the most premature babies. Early PH was associated with significant morbidity and mortality in excess of 50%. A renewed focus on the underlying pathophysiology and prevention of PH is warranted.