[Breech presentation (author's transl)].

The perinatal mortality and morbidity of 303 breech deliveries was investigated. In 80 newborn the acidosis (pH less than 7.20) was due to positional variations such as footling, knee and mixed breech presentations in vaginal deliveries. Our results are incorporated in a new concept of triage which permits continuing vaginal breech deliveries as a calculable risk.