Researchers at the French National Institute of Health and Medical Research (Inserm) reported that survival rates among premature babies have increased in recent years, but these children still have a high risk for developmental setbacks.
A study reporting the findings titled, “Neurodevelopmental outcome at 2 years for preterm children born at 22 to 34 weeks’ gestation in France in 2011: EPIPAGE-2 cohort study,” was published in the British Medical Journal (BMJ).
Survival of premature babies has increased worldwide as severe neonatal morbidity rates have declined. However, the risk of neurodevelopmental and behavioral disabilities remains high in babies born preterm. This includes cerebral palsy, deafness, and blindness, among other problems.
Most recent studies have focused on extremely premature babies born between 22 and 26 weeks of gestation, whereas studies on children born very and moderately preterm — between 27 and 34 weeks — have rarely been reported. That makes it challenging for doctors to identify children who are most at risk of developmental delays later in life.
Using the EPIPAGE 2 study, Inserm researchers followed more than 5,000 babies born in France in 2011 between 22 and 34 weeks of gestation. Results were compared with data reported in 1997, according to a news release.
The study included three groups of premature children: extreme premature (22-26 weeks), very premature (27-31 weeks), and moderately premature (32-34 weeks). Children were studied from birth until they were 12 years old.
Results showed that in France, a significant increase occurred in two-year survival rates: 51.7% for babies born at 22-26 weeks of gestation, 93.1% at 27-31 weeks, and 98.6% at 32-34 weeks.
Data on cerebral palsy were available for 3,599 babies, and the percentage of babies born at 24-26, 27-31, and 32-34 weeks who had the condition was 6.9%, 4.3%, and 1%, respectively. This percentage decreased overall by 3.3% between 1997 and 2011, a statistically significant result among babies born at 24-31 and 32-34 weeks’ gestation.
“The decline in the rates of cerebral palsy that we observed is consistent with those of cerebral palsy registers describing a decreased prevalence of cerebral palsy over time, and a substantial reduction in the most severe forms, especially in very low and moderately low birthweight neonates,” the research team wrote.
The Ages and Stages Questionnaire (ASQ) was used to screen children for developmental delays, after excluding children with cerebral palsy, deafness, blindness, or severe congenital brain malformations. In total, 50.2%, 40.7%, and 36.2% of children born at 24-26, 27-31, and 32-34 weeks, respectively, had lower than normal ASQ scores. Communication and personal-social skills were the most affected.
Regarding survival without severe or moderate neuromotor or sensory disabilities, the percentage among children born at 25-26 weeks’ gestation also increased between 1997 and 2011 from 45.5% to 62.3%. However, no change was observed in babies born at 22-24 weeks’ gestation, and for those born at 32-34 weeks’ gestation, a non-statistically significant increase in survival was observed.
“In this large cohort of preterm infants, rates of survival and survival without severe or moderate neuromotor or sensory disabilities have increased during the past two decades, but these children remain at high risk of developmental delay,” the researchers concluded.
The team suggested that conducting parental questionnaires to assess development may allow an early identification of children at risk for later difficulties. But they emphasized that this is an observational study, and no firm conclusions can be drawn about cause and effect.