Management of the selected term breech presentation: assessment of the risks of selected vaginal delivery versus cesarean section for all cases.

In this study, the concepts of decision theory have been applied to a clinical obstetric controversy--the management of the selected mature breech presentation. We have reviewed in detail the literature published since 1974 and estimated the probabilities of various outcomes after different treatment strategies. We conclude that a policy of selected vaginal delivery will result in four perinatal deaths for every 1000 patients delivered. A similar probability of neurologic handicap, at least until discharge from hospital, can also be attributed to this method of delivery. These unfavorable outcomes were reported less frequently in more recent reports covering the years since 1974. In these cases, the probability of fetal death due to a trial of vaginal delivery is approximately two in 1000. Cesarean section rates have risen, however, and 18-40% of trials of labor for breech presentation now result in "emergency" cesarean section. Decision analysis has demonstrated that a policy of elective cesarean section for all cases would not necessarily increase maternal mortality and morbidity. Thus the greater dangers of emergency compared with nonelective surgery may abolish the advantages of attempting a vaginal delivery. Depending on the relative dangers of elective and emergency cesarean section, planned delivery becomes the safer option when 16-30% of trials of vaginal breech delivery are unsuccessful. The strength and limitations of this probabilistic approach to the breech presentation are discussed in detail.