Table 2.

Time trends in caesarean section rates in all women and by parity (438 hospitals in China in 2012-16)

Variables	2012	2013	2014	2015	2016	P value (interaction)
Weighted caesarean section rate (%) (No of caesarean sections, % of caesarean sections)
All	45.3 (617 460, 100.0)	45.6 (606 607, 100.0)	43.8 (660 154, 100.0)	42.1 (561 127, 100.0)	41.1 (632 753, 100.0)	-
Nulliparous	46.6 (415 530, 67.4)	46.7 (393 807, 64.9)	43.3 (397 980, 60.3)	40.5 (300 413, 53.6)	37.9 (308 308, 48.7)
Multiparous without uterine scar	25.4 (84 711, 13.8)	24.9 (84 600, 14.0)	22.7 (90 494, 13.7)	20.5 (78 339, 14.0)	18.5 (84 100, 13.3)
Multiparous with uterine scar	90.3 (116 049, 18.8)	90.9 (127 559, 21.1)	91.0 (171 257, 26.0)	90.5 (181 811, 32.4)	90.4 (239 892, 37.9)
Crude relative risk (95% CI): model 1
All	1.00	1.01 (0.99 to 1.02)	0.97 (0.95 to 0.98)	0.93 (0.91 to 0.95)	0.91 (0.89 to 0.93)	-
Nulliparous	1.00	1.00 (0.99 to 1.02)	0.93 (0.91 to 0.95)	0.87 (0.85 to 0.89)	0.81 (0.79 to 0.84)	0.00
Multiparous without uterine scar	1.00	0.98 (0.92 to 1.01)	0.89 (0.86 to 0.93)	0.81 (0.77 to 0.84)	0.73 (0.70 to 0.76)
Multiparous with uterine scar	1.00	1.01 (1.00 to 1.01)	1.01 (1.00 to 1.01)	1.00 (1.00 to 1.01)	1.00 (0.99 to 1.01)
Adjusted relative risk (95% CI): model 3
All	1.00	0.99 (0.98 to 1.00)	0.93 (0.91 to 0.94)	0.87 (0.86 to 0.89)	0.82 (0.81 to 0.84)	-
Nulliparous*	1.00	0.99 (0.98 to 1.01)	0.91 (0.89 to 0.93)	0.85 (0.83 to 0.87)	0.78 (0.76 to 0.80)	0.00
Multiparous without uterine scar*	1.00	0.97 (0.95 to 1.00)	0.88 (0.85 to 0.91)	0.78 (0.75 to 0.82)	0.69 (0.66 to 0.72)
Multiparous with uterine scar*	1.00	1.00 (1.00 to 1.01)	1.00 (1.00 to 1.01)	0.99 (0.99 to 1.00)	0.99 (0.98 to 0.99)

6925 (0.1%) births had no information on parity and presence of uterine scar.

^*Model 3 without adjustment for Robson classification.