This study, a precursor, so to speak, of Epipage 2, began in 1997. Epipage 1 studied all births before 33 weeks of gestation in 9 regions of France, together with two other samples of children, one born at 33-34 weeks and the other at term.
Its objectives were to assess the outcome of these very preterm babies, to analyze the role of some factors in the etiology of sequelae (long-term effects), and to assess the impact of the organization of perinatal care and management during childhood.
The Epipage 1 cohort included 3 groups of children:
- All births between 22 and 32 weeks in 1997 in 9 regions: Alsace, Franche-Comté, Languedoc-Roussillon, Lorraine, Midi-Pyrénées, Nord-Pas-de-Calais, Haute-Normandie, Paris and its immediate suburbs (6 months), the Loire River region (3 departments) (2901 liveborn children).
- A group of moderately preterm children (33-34 weeks), recruited over only 2-month period (427 liveborn children), to determine if the period between 32 and 33 weeks is a real threshold for the risks of complications and long-term sequelae or if instead there isn't at least some continuity.
A group of control children born at term (39-40 weeks) and recruited during a single week (666 liveborn children), served as a reference group, in particular to provide an internal reference group for the analysis of child development.
Overall, 96% of parents agreed to participate in the study. The follow-up study thus tracked 2573 very preterm infants, 347 born at 33 or 34 weeks, and 558 born at term.
Contacts were established with the families to collect information about the children's health and development, first from discharge to age 5, specifically at 2 months after discharge, at 9 months of age, 1 year, and 2, 3, and 4 years. Children were offered a complete health examination at the age of 5 years. It included a medical examination and an examination performed by a psychologist. Almost 80% of families participated in this follow-up. At 8 years, a questionnaire sent to the families allowed us to collect information about the child's schooling. A survey of district centers for people with disabilities enabled us to identify the children with a recognized disability and to obtain additional information.
What are the principal results of this study ?
Outcome at 5 years of very preterm babies
At the age of 5 years, nearly 40% of the very preterm children had at least one motor, sensory, or cognitive disorder, compared with 12% of the children born at term. Nonetheless, only 5% presented the most severe forms; 9% had moderate damage and 25% mild.
9% of these children born very preterm had cerebral palsy (a motor disability of cerebral origin, expressed by motor disorders). One third of these children did not walk or walked only with assistance, but nonetheless 2/3 walked without assistance.
32% had a cognitive capacity score, equivalent to an IQ (intellectual quotient) below 85 and 12% below 70, compared with 12% and 3% respectively in the group of children born at term.
Visual and auditory damage remained rare in this population-approximately 1%. The impairment rates were highest for the children born earliest, for motor impairments as well as for visual or cognitive deficits. Accordingly, 18% of the children born at 24-26 weeks had cerebral palsy at 5 years, compared with 12% of those born at 29 weeks, and 4% of those born at 32 weeks.
At this age, a third of the preterm children followed still required specialized medical or therapeutic care: 42% of those born from 24 to 28 weeks and 31% of those born from 29 to 32 weeks, compared with 16% of those born at term.
Outcome at 8 years of very preterm babies
At the age of 8 years, information about schooling was collected with postal questionnaires sent to the parents of children born very preterm and of those born at term. All of the very preterm babies whose parents responded (1441 children) were in school: 95% in regular classes, 5% in special classes or institutions, compared with 99% an 1%, respectively, in children at term for whom this information was available (327 children).
Among the children in regular classes, 18% of the very preterm group had repeated a grade at least once; in the term group, this rate was 5%.
An assessment at 16 years
In 3 of the Epipage 1 regions (Paris and its immediate suburbs, Haute-Normandie, and the Loire River region), a follow-up that was not initially planned is underway to ascertain the general health status, and more particularly, the respiratory outcome of very preterm babies, using a questionnaire and lung function testing.