The information below reflects the state of knowledge in 2010, prior the launch of the Epipage2 cohort study.
In industrialized countries, between 5% and 12% of births occur before the normal term of pregnancy. In France, there are 60 000 each year, 10 000 (1.2%) before 32 weeks of gestation, and their numbers have been growing regularly. One of every 5 preterm babies is very premature.
There are two types of preterm birth — induced and spontaneoux.
Induced or iatrogenic preterm birth is induced by physicians who, in the presence of factors potentially threatening the mother's or child's survival, decide to end the pregnancy by inducing labor or by performing a cesarean. For example, the mother's life may be in danger because of preeclampsia (gestational hypertension related to the placenta), or the fetus's life may be threatened by the slowing of fetal growth.
During a so-colled spontaneous preterm birth, labor begins before the pregnancy has reached a normal term. We do not know the reasons for preterm labor, but it may be associated with an infectious environment. Premature rupture of the membranes (amniotic sac) can also cause spontaneous preterm birth.
On average, 60% of preterm deliveries are spontaneous, and 40% induced by physicians. The causes and conditions reponsible for these two large groups of preterm births are very different. The causes of preterm birth remain largely unknown, especially beacause they are multiple. They probably result from maternal or fetal complications and from placental abnormalities.
What Are the Consequences of Preterm Birth ?
In the short term
The neonatal mortality (death of children in the first month of life) rate exceeds 10% for the very preterm infants (<32 weeks), and is 2-3% for those moderately preterm (32-33 weeks), and 0.5-1% for those born at 34-36 weeks, compared with less than 2 per 1000 children born at term.
In the longer term
The risks described most often are motor disabilities and intellectual impairment. As the table below shows, the earlier the preterm birth, the higher the risk.
|Motor disabilities||Intellectual impairment|
|Very perterm birth (<32 weeks)||10%||15%|
|Moderate preterm birth (32-33 weeks)||4%||10%|
|Late preterm birth (34-36 weeks)||0.5%||5%|
Management and care of pregnant women and children have changed over the last 15 years. These changes might have affected the health and development of these preterm children. It is thus essential to measure them with precision. The Epipage 2 study will improve our knowledge of the prognosis of preterm birth by studying children's overall health status (growth, metabolism, allergies, and respiratory diseases) and development, including psychiatric disorders, learning disorders, severe disabilities, and quality of life.