The incidence, risk factors and maternal and foetal outcomes of uterine rupture during different birth policy periods: an observational study in China

Table 2 The risk of uterine rupture by age, parity and number of previous caesarean sections in China

Maternal characteristics	Number of uterine ruptures (%)	Weighted rate, per 100 births^a	Crude odds ratio^a	Adjusted odds ratio^a
Maternal age^b
< 24	1105 (8.54)	0.05	1	1
24–29	3949 (30.53)	0.10	2.11 (1.71–2.62)	0.91 (0.78–1.07)
30–34	4830 (37.34)	0.23	4.67 (3.45–6.34)	0.91 (0.72–1.14)
≥ 35	2831 (21.89)	0.29	6.05 (4.02–9.10)	0.83 (0.66–1.04)
Missing	219 (1.69)	0.07	1.40 (0.94–2.10)	0.55 (0.38–0.79)
Parity^c
0	948 (7.33)	0.02	1	1
≥ 1
All	–	0.26	14.69 (9.31–23.20)	2.17 (1.43–3.29)
1	9698 (74.98)	0.26	14.21 (8.85–22.81)	2.21 (1.45–3.37)
2	1966 (15.20)	0.32	17.74 (11.55–27.26)	2.60 (1.68–4.02)
≥ 3	225 (1.74)	0.21	11.46 (7.28–18.04)	2.57 (1.66–3.99)
Missing	97 (0.75)	0.91	50.92 (25.49–101.72)	2.79 (0.91–8.57)
Previous caesarean sections^d
0	1545 (11.95)	0.02	1	1
≥ 1
All	–	0.75	39.85 (26.99–58.84)	11.33 (8.59–14.96)
1	9797 (75.75)	0.70	37.42 (25.04–55.94)	10.69 (8.15–14.02)
≥ 2	1478 (11.43)	1.50	79.52 (53.76–117.62)	19.93 (13.16–30.20)
Missing	114 (0.88)	0.29	15.38 (2.94–80.42)	1.29 (0.34–4.87)
Total	12,934 (100.00)	0.13	–	–

^aWeighted for the sampling distribution of the population covered by the Chinese National Maternal Near Miss Surveillance System
^bWe did not adjust for maternal age in the different age groups
^cWe did not adjust for parity in the different parity groups
^dWe did not adjust for previous caesarean sections in different groups of previous caesarean sections