Demographics and caesarean delivery rates
Overall, there were 103,165 births in the cohort. After exclusions,
102,589 births with complete data remained for analysis: 48,215 in Group
A, and 54,374 in Group B (Figure S1). On average, women in Group B were
older and were more likely to be overweight or obese (Table 1). Group B
also had a greater proportion of nulliparous women (50% vs 46%), and
more women with a previous caesarean delivery (24% vs 14% of births to
parous women, 12% vs 7.5% of all births).
The overall caesarean delivery rates were 19% in Group A and 30% in
Group B (Table 2). Over the two time-periods, planned caesarean delivery
increased from 9.7% to 19% and emergency caesarean delivery increased
from 9.4% to 11.6% of all births (Table 2). The rate of caesarean
delivery in women with no previous caesarean delivery increased from
15% to 23% and the rate in nulliparous women increased from 20% to
30%.