Survival and place of delivery following preterm birth: 1994-96

Aim-To compare the survival of premature infants, adjusted for disease seve rity, in different types of neonatal intensive care setting. Methods-A prospective observational study in the Trent Health Region was ca rried out of all infants born to resident mothers at or before 32 weeks of gestation between 1 January 1994 to 31 December 1996 inclusive, The 16 neon atal units in Trent were subdivided into five relatively large units which regularly took outside referrals and 11 smaller units which provided intens ive care for a variable proportion (sometimes nearly 100%) of their local p opulation. Data regarding obstetric management, neonatal care, and outcome were collected by independent neonatal nurses who visited the units on a re gular basis. Survival rates were compared with an expected rate calculated using the Clinical Risk Index for Babies (CRIB). For either setting to be a bnormally good or bad actual deaths had to exceed the 95% confidence interv al of the CRIB estimate. Results-Actual survival rates for infants less than or equal to 32 weeks ge station and for the group of babies less than or equal to 28 weeks gestatio n fell within the 95% confidence interval of the rate predicted by CRIB for both the larger referral units and the smaller district units. Similarly, compared with the CRIB prediction, infants transferred in utero or postnata lly were not adversely affected in terms of the number who died. Conclusion-Previous results from this geographical population, showing that survival of babies less than or equal to 28 weeks gestation was better whe n their care was provided by referral units, are no longer sustained. Signi ficant changes to the neonatal services over time make the current results plausible. However, the new structure poses potential threats to the teachi ng, training, and research base of the neonatal service as a whole.