RESUMO
OBJECTIVE: In view of the high frequency rates of cesarean section at the Instituto Mexicano del Seguro Social (IMSS), we carried out a study to know main causes and its justification. MATERIAL AND METHOD: Retrospective study in a randomized national sample of clinical records in 3,232 cesarean cases between June 1997 and June 1999. RESULTS: The most frequent indications were cephalopelvic disproportion (29.6%), one previous section (20.9%), acute fetal distress (14.1%), iterative section (11.9%), and premature rupture of amniotic membranes (10.7%). In cephalopelvic disproportion cases, mean weight of newborns was 3,430 g., 70.6% of patients had irregular uterine contractility, and 21.7% received oxytocin; 78.2% had integrity of membranes and 4 cm or less in cervical dilation. In previous section and cephalopelvic disproportion the mean weight of newborns was 3,425 g; 81.7% did not have regular contractility and, 4.8 received oxytocin. In sections due to acute fetal distress, 94.9% had an Apgar in 8 or more at 5 minutes after delivery. CONCLUSION: The cesarean indications at the IMSS were similar to those are informed most to date in Mexico and throughout the world, but we did not find justification most of cases in this study.