Cesarean section: analysis of the experience before and after the National Consensus Conference on Aspects of Cesarean Birth.

OBJECTIVE

To examine the effect of recommendations to reduce the cesarean section rate issued by the National Consensus Conference on Aspects of Cesarean Birth in 1986 on obstetric practices and to identify current patient factors that predict cesarean section.

DESIGN

Descriptive retrospective cross-sectional study.

SETTING

A tertiary care perinatal referral centre and a general teaching hospital with a level 2 nursery in Hamilton, Ont.

PATIENTS

All patients who gave birth at the two hospitals in 1982 (4121 women) and 1990 (4431).

MAIN OUTCOME MEASURES

Cesarean section rates and indications and predictors of cesarean section.

RESULTS

Although a trial of vaginal delivery after cesarean section was offered 93% more often in 1990 than in 1982 (p = 0.0002), the rate of vaginal delivery increased only 2.6%, for a reduction of 8.7% in the total cesarean section rate and of 15% in the repeat cesarean section rate. The incidence rate and treatment of dystocia did not change. The rate of cesarean section for breech presentation remained unchanged, and fetal distress was rarely confirmed with pH measurement in scalp blood before cesarean section. The most important predictors of cesarean section in 1990 were previous cesarean section and labour induction. For the nulliparous women and the multiparous women with no previous cesarean section labour induction was the most important predictor.

CONCLUSIONS

The rate at which patients with previous cesarean section are offered a trial of vaginal delivery has increased significantly since 1982; however, the total and repeat cesarean section rates have not decreased proportionally. Induction of labour is currently the most important correctable predictor of cesarean section. The active management of dystocia, efforts to increase the rate of vaginal breech delivery and appropriate methods to diagnose fetal distress need to be improved; such improvements should reduce the cesarean section rate further.