[Retrospective analysis of 663 breech deliveries during the years 1976 to 1985].

663 breech deliveries between 1976 and 1985 at Hannover Medical School have been studied retrospectively. The overall frequency of breech deliveries was 4.5%. 6.1% were primigravid women. Comparisons were made to a group of deliveries with vertex presentation. Matched pairs were identical regarding the year of delivery, the method (vaginal delivery/caesarean section) and parity. 26.2% of breeches were born through the vagina. The frequency of vaginal deliveries after the 37th week of gestation ranged from 13.5% to 46.9% per year. For vaginal delivery the following prerequisites are defined at out institution: normal pelvic measures and physique, expected birth weight between 2500 g and 3500 g and informed consent. Until 1979 the frequency of vaginal deliveries ranged from 12% to 25%. Since 1980 an increasing number up to 45% was noted. For deliveries before the 38th week of gestation primary indicated caesarean section was preferred. The rate of maternal complications after caesarean section was high compared to vaginal deliveries (29.0% versus 8.6%; p less than or equal to 0.05). Also, these complications usually were more serious. Injuries of the newborn were more often observed following vaginal delivery than following caesarean section (7.5% versus 2.9%). No significant differences were found between the apgar scores after vaginal deliveries and caesarean sections. However, the percentage of reduced pH values was significantly higher after vaginal breech deliveries (57.5% versus 24.7%; p less than or equal to 0.05). No severe acidosis was observed. No difference was seen between the fetal outcome of deliveries from primiparous and multiparous women. Perinatal mortality according to WHO criteria was 1.1%.(ABSTRACT TRUNCATED AT 250 WORDS)