Table 2. Incidence, diagnosis, and mode of birth of term breech babies.

	Pre-universal 36-week scan	Post-universal 36-week scan	RR (95% CI)	p-value
N (total)	14,444	13,381
Breech presentation at birth, n (%)	380 (2.6)	360 (2.7)	1.02 (0.89–1.18)	0.76
Among all breech presentations at birth:	380	360
Planned vaginal breech birth, n (%)	13 (3.4)	22 (6.1)	1.79 (0.91, 3.49)	0.09
Actual vaginal breech birth, n (%)	39 (10.3)	19 (5.3)	0.51 (0.30, 0.87)	0.01
Elective CS, n (%)	218 (57.4)	241 (66.9)	1.17 (1.04, 1.31)	0.01
Emergency CS, n (%)	123 (32.4)	100 (27.8)	0.86 (0.69, 1.07)	0.18
Diagnosed before birth, n (%)	283 (74.5)	330 (91.7)	1.23 (1.15, 1.32)	<0.001
Gestational age at delivery (weeks), mean ± SD	39.1 (0.9)	39.0 (0.8)		0.02
Planned vaginal breech birth, n (%)	13 (4.6)	22 (6.7)	1.45 (0.74, 2.83)	0.27
Actual vaginal breech birth, n (%)	14 (5.0)	17 (5.2)	1.04 (0.52, 2.07)	0.91
Elective CS, n (%)	206 (72.8)	228 (69.1)	0.95 (0.86, 1.05)	0.31
Emergency CS, n (%)	63 (22.3)	85 (25.8)	1.16 (0.87, 1.54)	0.32
Breech undiagnosed before birth, n (%)**	97 (25.5)	30 (8.3)	0.33 (0.22, 0.48)	<0.001
Gestational age at delivery (weeks), mean ± SD	39.7 (1.3)	39.5 (1.2)		0.44
Planned vaginal breech birth, n (%)	0 (0.0)	0 (0.0)	NA	NA
Actual vaginal breech birth, n (%)	25 (25.8)	2 (6.7)	0.26 (0.07, 1.03)	0.06
Elective CS, n (%)	12 (12.4)	13 (43.3)	3.50 (1.79, 6.84)	<0.001
Emergency CS, n (%)	60 (61.9)	15 (50.0)	0.81 (0.55, 1.19)	0.29
Breech undiagnosed before labour***, n(%)	85 (22.3)	17 (4.7)	0.21 (0.12, 0.36)	<0.001

*p-Value from t test.

**Defined as breech presentation at delivery and either (1) no scan ≥35+0 weeks showing breech; (2) successful external cephalic version; or (3) no elective CS with breech presentation as primary/secondary indication.

***Labour started with undiagnosed breech: elective CS excluded.

CI, confidence interval; CS, cesarean section; NA, not applicable; RR, relative risk.