Term breech birth in New South Wales, 1990-1997

Data on 636,708 women delivering a singleton infant of gestational age > or =37 weeks in NSW from 1 January 1990 to 31 December 1997 were used to examine trends in breech births at term and the mode of delivery. From 1990 to 1997, although the crude rate of breech births at term remained stable at 3.4%, the adjusted odds ratio for breech birth compared with cephalic birth decreased over time. Among live breech births, the crude rate of vaginal breech birth declined from 29.4% to 19.7%, with an attendant increase in elective Caesarean sections from 49.1% to 58.4%. Most of this increase was at 38 and 39 weeks gestation. There was no change in the perinatal mortality rate among breech births during the study period. Despite increasing maternal age, the adjusted odds of a breech birth at term decreased over time. This could be due to offsetting factors, such as increased use of external cephalic version. If the decrease in vaginal breech birth continues, it may lead to the skills for this procedure being lost.