Background Mortality rates for very preterm births (VPTBs) show wide variation across Europe. Some, of this variation can be explained by a lack of standardised data collection and reporting. Using the standardised EPICE population-based cohort of VPTBs we investigate the potential explanatory factors for the variation in the in-hospital mortality rates between 19 European study regions.

Methods All births between 22⁺⁰ and 31⁺⁶ weeks of gestational age were included in the EPICE birth cohorts in 19 regions in 11 European countries. A standardised data collection system was established in each of the regions; ascertainment was validated against birth registers. All VPTBs were followed to death or discharge home from neonatal care. Mortality rates were calculated for the total cohort (~10,000), live born infants and those admitted for neonatal care. Assessment of the potential maternal and infant explanatory factors for the variations in standardised mortality rates were investigated using multilevel logistic regression.

Results Crude in-hospital mortality rates for (i) total very preterm birth cohort 22⁺⁰ to 31⁺⁶ weeks gestation (excluding TOPs for congenital anomaly), ranged from 19.5% to 48.9% by region; (ii) all live births: 6.7–20.9% and (iii) for admissions to neonatal care: 4.9–18.3%. Following adjustment for maternal and infant characteristics the variation in these rates reduced to: total cohort 23.5–39.3%; live births 10.2–17.7% and NIC admissions 7.5–15.2%.

Conclusions Only a small proportion of the variation in the standardised mortality rates was explained by the maternal and infant characteristics. Further work will investigate variation in the timing of death.