Impact of sex ratio on onset and management of labour.

In a study of 52,266 live singleton deliveries in a total population male babies were delivered at earlier gestations than female. This difference was not due to induction or elective caesarean section. Female babies were more likely to present and be delivered by the breech. When the presentation was cephalic, male babies were much more likely to be delivered by forceps or caesarean section and female babies to deliver spontaneously.