[Women with previous caesarean or other uterine scar: epidemiological features]

To describe the prevalence of uterine scar and the risk of associated obstetrical complications and current modes of delivery in women with a previous cesarean.

Consultation of the Medline database, and of the National Perinatal Surveys data.

Previous cesarean is the main cause of uterine scar. In France, the cesarean rate increased from 15.5% in 1995 to 20.8% in 2010; as a consequence, the prevalence of previous cesarean also increased from 8 to 11% of parturients and from 14 to 19% of multiparas, between 1995 and 2010. Previous cesarean is, in developed countries, the main risk factor for uterine rupture, whose global incidence is estimated between 0.1 and 0.5% in parturients with previous cesarean. Women with previous cesarean also are at higher risk for abnormal placenta insertion, the strength of the association increasing with the number of previous cesareans: twice higher risk of placenta praevia and greater maternal morbidity associated with placenta praevia; major risk factor for placenta accreta in particular in women combining previous cesarean and placenta praevia. Modes of delivery in women with previous cesarean vary widely between countries. According to the 2010 National Perinatal Survey, in France, 51% have a cesarean before labor; among those with a trial of labor, 75% deliver vaginally; in total, 36.5% have a vaginal delivery.

The prevalence of uterine scar is increasing, following the rise in cesarean rate. This condition is a risk factor for obstetrical complications in subsequent pregnancies. Women with multiple previous cesareans are particularly at risk.