Table 3.

Time from retracted cervix to vaginal birth and risk of any maternal complication during the early postpartum period stratified by mode of delivery

Time from retracted cervix to birth (hours)	Primiparous				Parous, previous caesarean				Parous, no previous caesarean
	n	%	aORa	95% CI	n	%	aORa	95% CI	n	%	aORa	95% CI
Any maternal complication in noninstrumental vaginal deliveries
	Primiparous (n = 30 649)				Parous, previous caesarean (n = 2636)				Parous, no previous caesarean (n = 28 953)
<1	348	3.0	1.00	Reference	67	4.6	1.00	Reference	322	1.3	1.00	Reference
1 to <2	393	4.1	1.27	1.09–1.48	45	7.0	1.47	0.96–2.25	89	3.2	2.19	1.69–2.84
2 to <3	283	5.4	1.56	1.31–1.85	19	6.0	1.32	0.75–2.31	34	4.3	2.80	1.89–4.15
3 to <4	151	5.3	1.54	1.24–1.89	18	10.8	2.33	1.28–4.25	11	4.5	2.74	1.42–5.30
≥4	91	6.5	1.80	1.40–2.33	10	16.1	3.48	1.56–7.76	3	4.2	2.60	0.80–8.42
Any maternal complication in instrumental vaginal deliveries
	Primiparous (n = 7769)				Parous, previous caesarean (n = 663)				Parous, no previous caesarean (n = 1034)
<1	64	5.2	1.00	Reference	15	10.2	1.00	Reference	16	3.5	1.00	Reference
1 to <2	113	6.9	1.22	0.88–1.70	26	14.3	1.84	0.88–3.88	20	7.8	1.71	0.79–3.71
2 to <3	125	7.6	1.27	0.92–1.76	16	11.6	1.60	0.70–3.65	11	7.5	2.21	0.91–5.39
3 to <4	134	7.9	1.38	1.00–1.91	16	13.7	2.01	0.86–4.69	11	10.2	3.30	1.30–8.37
≥4	151	9.7	1.71	1.24–2.35	8	10.1	1.06	0.38–2.95	4	6.6	2.03	0.60–6.90

^aAdjusted for maternal age, height, body mass index, parental cohabitation, smoking, induction of labour, gestational age epidural analgesia and oxytocin augmentation.