[Preterm labor: pathophysiology, risk factors and outcomes].

Preterm labor (PL) is the main cause for hospital admission during pregnancy. 50% of all pregnant women are diagnosed with PL. 7% of all neonates are born prematurely and one third of all preterm births follow PL with intact membranes. Previous history of preterm delivery, young maternal age, low socio-economical status are established risk factors of PL with intact membranes. Intrauterine infection, abruptio placenta praevia and uterine and cervical anomalies are often associated with PL with intact membranes. Cytokines, cortico-releasing hormone and the fetal hypothalamic-pituitary-adrenal axis could trigger the prostaglandin cascade leading to PL. However data are lacking to conclude. Intrauterine infection can also lead to neonatal infection in the preterm babies. This is also an important risk factor of cerebral lesions and cerebral palsy. Outside perinatal infection, PL does not seem to increase neonatal death and neonatal morbidity compared with other causes of preterm delivery.