[Risk factors for cesarean section: epidemiologic approach].

The increase in frequency of cesareans that has been noted through 70's, not diminished--like it was expected--perinatal morbidity and mortality. The most important indications to cesarean are distocias, previous cesarean and fetal stress. In 1998 frequency of cesarean deliveries in our hospital was 35% of the pregnancy attended. The claim of this study was to determine risks factors to cesarean in our hospital. A case-control study was performed, selecting 165 cases (cesareans) and 328 controls (via vaginal). It was determined OR of the risks factors and atribuible fraction. Data were analyzed by X2. The most important indications to cesarean delivery were: distocias (39%, n = 64); previous cesarean (23%, n = 41) and fetal stress (11%, n = 21). There was not significative differences in age, height and rupture membrane time in both groups. History of cesarean delivery gave major risk to another surgical intervention (OR = 12.7, p = < 0.0001, atribuible fraction 92%). Nuliparous (OR = 6.6, p < 0.00000, atribuible fraction 85%), second gestation (OR = 1.8, p = 0.002) or history of abortion (OR = 1.8, p = 0.04) were factors mainly associated to cesarean delivery. We concluded that the precise 'medications of this surgical intervention specially in nuliparous or previous cesarean delivery cases must be replanteated to diminish its elevated frequency.