HI everyone -- thanks for additional replies! Revised stats.
PREGNANCY LENGTHS:
39+7d pregn. length everybody
39+4d pregn. length if spontaneious start
HOW LABOUR STARTED:
62.3% labour started spontaneously
30.8% labour induced with more than sweep or gel,
and led to C-section
INDUCTIONS
7.02% induced with only gel/sweep
5.26% premature births (before 36 weeks)
10.53% induced leading to birth after 41wks+4 days, including just induced by sweeps/gel
C-SECTIONS:
7.02% scheduled-C-section
20.2% C-section rate (however labour started)
7.04% C-section rate if labour started spontaneously
41.7% induced after 41 wks+4 days that led to C-section
4.4% of everybody, apparently induced for going over dates and then leading to a C-section
So, if you (apparently) were induced for going over dates, you had a whopping 42% risk of C-sections. I wonder if that's true for the general population! Ouch. I'm not out to start a debate about C-sects, but it's a stat to keep in mind when weighing up the risks of going past 42 weeks.
Although the risk of being one of those people whose pregnancy ends in failed induction for going over dates resuling in C-section, is only about 4.4%.
SuzyW: I could collect DH's ethnicity... but I think mother's ethnic group would be much more important, and all I could do here was try to pick out Celtic mums (Scots/Welsh/Irish) versus others. At a glance (all the data are good for) the Celts follow much same pattern as everyone else.