Temporal trends of in utero and early postnatal transfer of extremely preterm infants between 2011 and 2016: a UK population study

Objective Early postnatal transfer (PNT) of extremely preterm infants is associated with adverse outcomes compared with in utero transfer (IUT). We aimed to explore recent national trends of IUT and early PNT. Design Observational cohort study using the National Neonatal Research Database. Setting Neonatal units in England, Scotland and Wales. Patients Extremely preterm infants 23(+0)-27(+6) weeks' gestation admitted for neonatal care from 2011 to 2016. Main outcome The incidence of IUT or PNT within 72 hours of life. Secondary outcomes included mortality, hospital transfer level between centres and temporal changes across two equal epochs, 2011-2013 (epoch 1 (Ep1)) and 2014-2016 (epoch 2 (Ep2)). Results 14 719 infants were included (Ep1=7363 and Ep2=7256); 4005 (27%) underwent IUT; and 3042 (20.7%) had PNT. IUTs decreased significantly between epochs from 28.3% (Ep1=2089) to 26.0% (Ep2=1916) (OR 0.90, 95% CI 0.84 to 0.97, p<0.01). Conversely, PNTs increased from 19.8% (Ep1=1416) to 21.5% (Ep2=1581) (OR 1.11, 95% CI 1.02 to 1.20, p=0.01). PNTs between intensive care centres increased from 8.1% (Ep1=119) to 10.2% (Ep2=161, p=0.05). Mortality decreased from 21.6% (Ep1=1592) to 19.3% (Ep2=1421) (OR 0.90, 95% CI 0.83 to 0.97, p=0.01). Survival to 90 days of age was significantly lower in infants undergoing PNT compared with IUT (HR 1.31, 95% CI 1.18 to 1.46), with the greatest differences observed in infants Conclusion In the UK, IUT of extremely preterm infants has significantly decreased over the study period with a parallel increase in early PNT. Strategies to reverse these trends, improve IUT pathways and optimise antenatal steroid use could significantly improve survival and reduce brain injury for these high-risk infants. Between 2011 and 2016, the rate of intra-uterine transfer of extremely preterm infants within the UK decreased, with an associated increase in early postnatal transfer. This also includes early postnatal transfer between level 3 NICUs.