Intended for healthcare professionals


Survival of extremely premature babies in a geographically defined population: prospective cohort study of 1994-9 compared with 2000-5

BMJ 2008; 336 doi: (Published 29 May 2008) Cite this as: BMJ 2008;336:1221
  1. David J Field, professor of neonatal medicine1,
  2. Jon S Dorling, consultant neonatologist2,
  3. Bradley N Manktelow, medical statistician1,
  4. Elizabeth S Draper, professor of perinatal and paediatric epidemiology1
  1. 1Department of Health Sciences, University of Leicester, Leicester
  2. 2Nottingham University Hospitals Trust, Neonatal Unit, Nottingham City Hospital Campus, Nottingham
  1. Correspondence to: D Field, Neonatal Unit, Leicester Royal Infirmary, Leicester LE1 5WW david.field{at}
  • Accepted 3 April 2008


Objective To assess changes in survival for infants born before 26 completed weeks of gestation.

Design Prospective cohort study in a geographically defined population.

Setting Former Trent health region of the United Kingdom.

Subjects All infants born at 22+0 to 25+6 weeks’ gestation to mothers living in the region. Terminations were excluded but all other births of babies alive at the onset of labour or the delivery process were included.

Main outcome measures Outcome for all infants was categorised as stillbirth, death without admission to neonatal intensivecare, death before discharge from neonatal intensivecare, and survival to discharge home in two time periods: 1994-9 and 2000-5 inclusive.

Results The proportion of infants dying in delivery rooms was similar in the two periods, but a significant improvement was seen in the number of infants surviving to discharge (P<0.001). Of 497 infants admitted to neonatal intensive care in 2000-5, 236 (47%) survived to discharge compared with 174/490 (36%) in 1994. These changes were attributable to substantial improvements in the survival of infants born at 24 and 25 weeks. During the 12 years of the study none of the 150 infants born at 22 weeks’ gestation survived. Of the infants born at 23 weeks who were admitted to intensive care, there was no significant improvement in survival to discharge in 2000-5 (12/65 (18%) in 2000-5 v 15/81 (19%) in 1994-9).

Conclusions Survival of infants born at 24 and 25 weeks of gestation has significantly increased. Although over half the cohort of infants born at 23 weeks wasadmitted to neonatalintensive care, there was no improvement in survival at this gestation. Care for infants born at 22 weeks remained unsuccessful.


  • We thank all the health professionals who were involved in the data collection.

  • Contributors: JSD, ESD, BNM, and DJF developed the idea for the paper and drafted the paper. ESD and DJF designed the study. BM performed the statistical analysis, and JSD, ESD, BM, and DJF interpreted the results. All authors revised the paper critically and approved the final manuscript. DJF is the guarantor.

  • Funding: NHS research and development funds from healthcare commissioners in the Trent region.

  • Competing interests: None declared.

  • Ethical approval: Local research ethics committee approval was obtained for each of the centres at the beginning of the Trent Neonatal Survey. In 2004 approval was obtained from the Trent multicentre research ethics committee. The neonatal survey obtained section 60 approval under the Health and Social Care Act for its programmes in 2002. The Patient Information Advisory Group also gave approval for collection of data without consent.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Accepted 3 April 2008
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