Very Preterm Birth Remains Linked to Long-Term Problems

Jennifer Garcia

December 06, 2012

The results of 2 large cohort studies in the United Kingdom reveal that although more babies are surviving extreme preterm birth, the rate of serious health and developmental problems that persist into childhood remains unchanged. The results of both studies were published online December 4 in the British Medical Journal.

The studies, known as the EPICure studies, evaluated survival and outcome of preterm births (before 26 weeks of gestation) in 2006 and compared them with results for preterm infants born in 1995.

The first study, by Kate L. Costeloe, MB BCHir, FRCP, FRCPCH, from the Centre for Pediatrics, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom, and colleagues, prospectively evaluated survival and outcomes for 3133 neonates in 2006 from birth until discharge from hospital. At the time of discharge, 68% of the surviving infants had bronchopulmonary dysplasia and 13% had serious abnormalities on cerebral ultrasonography — proportions similar to those noted in 1995 — however, the proportion of those treated for retinopathy of prematurity had increased from 13% to 22% (P = .006).

The researchers found that the number of neonates born at 22 weeks to 25 weeks admitted in the intensive care unit increased by 44% from 666 in 1995 to 959 in 2006. Survival rates for these infants increased from 40% to 53% (P < .001) during this time; however, there was no improvement in the proportion of those leaving the hospital with major health problems.

"The emerging picture would seem to favour improved outcomes and yet the pattern of major neonatal morbidities is strikingly similar to that in 1995," write Dr. Costeloe and colleagues. "The most striking outcome of these analyses, however, is the consistency between the two cohorts and the lack of evidence, after adjustment for the condition of the baby shortly after birth, of improved survival or changed proportion of survivors with either bronchopulmonary dysplasia or severe abnormality on cerebral ultrasonography."

The second study, by Tamanna Moore, research associate, Academic Neonatology, University College London Institute for Women’s Health, London, and colleagues, evaluated the neurological and developmental outcomes at age 3 years in 576 babies born before 27 weeks in 2006 and compared these results with 260 babies of the same gestational age born in 1995. The study found that that although 11% more babies survived to age 3 years without disability in 2006 than in 1995, the proportion of survivors born between 22 and 25 weeks with severe disability was unchanged (18% in 1995 vs 19% in 2006) after accounting for missing data.

The researchers found that the most common problem was developmental or cognitive dysfunction and that in 2006, the rate of severe disability at age 3 years increased as gestation time shortened, from 20% at 26 weeks to 45% at 22 to 23 weeks of gestation (P < .001).

The researchers in both studies note that despite the implementation of evidence-based interventions to improve outcomes, the rate of serious long-term outcomes has changed little during the last 10 years. They note that these long-term health problems will have a significant effect on health, education, and social services over time but caution that "[o]nly assessment of the 2006 cohort at school age will clarify whether there have been important changes in the high prevalence of impaired cognitive and behavioural outcomes."

"The seeming improvement in both survival and disability-free survival is encouraging but offset against a lack of reduction in the prevalence of severe disability in our population," Moore and colleagues write.

"Current research should be directed at biomarkers that accurately predict later outcomes. Further perinatal and neonatal studies could then target these, and the biomarkers themselves could be used to focus interventions for children at high risk," they conclude.

Funding for both studies was provided by the Medical Research Council. The authors have disclosed no relevant financial relationships.

BMJ. Published online December 4, 2012. Costeloe full text, Moore full text