. 2022 Oct 14;17(10):e0275879. doi: 10.1371/journal.pone.0275879

Table 3. Risk of type specific postpartum hemorrhage (PPH >500ml) according to maternal, pregnancy and birth characteristics; singleton births, ≥22 weeks of gestation and spontaneous onset or induction of labor.

		Total	Retained placenta					Atony					Trauma or laceration					Dystocia					Undefined bleeding cause
		(n)	(n)	%	aOR	95% CI		(n)	%	aOR	95% CI		(n)	%	aOR	95% CI		(n)	%	aOR	95% CI		(n)	%	aOR	95% CI
Maternal age (Years)	<20	136032	841	0.6	0.55	0.51	0.59	2507	1.8	0.82	0.79	0.86	1049	0.8	0.55	0.51	0.59	801	0.6	0.33	0.31	0.36	3815	2.8	0.85	0.83	0.89
	20–24	652556	5540	0.8	0.74	0.72	0.77	14209	2.2	0.92	0.90	0.94	6035	0.9	0.73	0.70	0.75	5829	0.9	0.56	0.54	0.58	21328	3.3	0.93	0.91	0.94
	25–29	916125	10647	1.2	1	Ref		24536	2.7	1	Ref		10600	1.2	1	Ref		13315	1.5	1	Ref		36781	4.0	1	Ref
	30–34	662257	10324	1.6	1.32	1.28	1.34	19722	3.0	1.03	1.01	1.05	7593	1.1	1.09	1.06	1.13	11806	1.8	1.42	1.38	1.46	31205	4.7	1.07	1.05	1.09
	35–39	260686	4932	1.9	1.62	1.56	1.68	8012	3.1	1.06	1.03	1.09	2751	1.1	1.16	1.10	1.22	4914	1.9	1.79	1.73	1.86	13969	5.4	1.17	1.14	1.20
	40–44	46563	929	2.0	1.75	1.62	1.89	1395	3.0	1.09	1.03	1.15	410	0.9	1.14	1.02	1.28	884	1.9	2.04	1.90	2.20	2819	6.1	1.34	1.29	1.40
	≥45	2198	43	2.0	1.97	1.43	2.70	76	3.5	1.40	1.11	1.76	26	1.2	1.80	1.18	2.74	48	2.2	2.50	1.83	3.41	164	7.5	1.79	1.53	2.09
Parity	0	1124388	15284	1.4	1	Ref		33966	3.0	1	Ref		18609	1.7	1	Ref		28690	2.6	1	Ref		50806	4.5	1	Ref
	1	935991	11389	1.2	0.77	0.75	0.79	23415	2.5	0.78	0.77	0.79	7409	0.8	0.42	0.41	0.44	6838	0.7	0.22	0.22	0.23	37766	4.0	0.86	0.85	0.88
	2	423535	4700	1.1	0.64	0.62	0.67	9225	2.2	0.66	0.65	0.68	1872	0.4	0.22	0.21	0.24	1511	0.4	0.10	0.09	0.11	14758	3.5	0.74	0.73	0.76
	3	128264	1273	1.0	0.55	0.51	0.58	2564	2.0	0.59	0.57	0.62	407	0.3	0.16	0.15	0.18	372	0.3	0.08	0.07	0.09	4305	3.4	0.71	0.69	0.74
	4	46957	412	0.9	0.48	0.43	0.53	868	1.8	0.52	0.57	0.62	131	0.3	0.14	0.11	0.16	135	0.3	0.08	0.06	0.09	1721	3.7	0.77	0.73	0.81
	≥5	17282	198	1.1	0.56	0.48	0.66	419	2.4	0.66	0.59	0.73	36	0.2	0.09	0.06	0.13	51	0.3	0.07	0.05	0.09	725	4.2	0.82	0.75	0.89
Previous 1st trimester spontaneous abortion ^a	No	818952	17401	2.1	1	Ref		35221	4.3	1	Ref		16047	2.0	1	Ref		25314	3.1	1	Ref		60431	7.4	1	Ref
Previous 1st trimester spontaneous abortion ^a	Yes	188824	5032	2.7	1.24	1.19	1.28	8437	4.5	1.09	1.07	1.12	3118	1.7	0.97	0.93	1.02	5362	2.8	1.07	1.04	1.11	13960	7.4	0.99	0.97	1.01
1st trimester bleeding	No	2628264	31692	1.2	1	Ref		68462	2.6	1	Ref		27927	1.1	1	Ref		36477	1.4	1	Ref		107109	4.1	1	Ref
1st trimester bleeding	Yes	48153	1564	3.2	2.10	1.99	2.22	1995	4.1	1.28	1.22	1.34	537	1.1	0.83	0.75	0.91	1120	2.3	1.10	1.03	1.17	2972	6.2	1.16	1.12	1.21
Previous cesarean section	No	2560531	31040	1.2	1	Ref		66385	2.6	1	Ref		25783	1.0	1	Ref		33216	1.3	1	Ref		101631	4.0	1	Ref
Previous cesarean section	Yes	115886	2216	1.9	1.39	1.33	1.46	4072	3.5	1.27	1.22	1.31	2681	2.3	3.41	3.25	3.58	4381	3.8	6.08	5.82	6.35	8450	7.3	1.55	1.52	1.59
Start of labor	Spontaneous	2247799	25951	1.2	1	Ref		54953	2.4	1	Ref		22128	1.0	1	Ref		26318	1.2	1	Ref		84815	3.8	1	Ref
Start of labor	Induction	428618	7305	1.7	1.36	1.32	1.39	15504	3.6	1.41	1.38	1.43	6336	1.5	1.31	1.27	1.35	11279	2.6	1.87	1.82	1.91	25266	5.9	1.45	1.43	1.47
Birthweight (grams)	<2500	91074	1443	1.6	1.39	1.32	1.47	1073	1.2	0.42	0.39	0.45	245	0.3	0.22	0.19	0.25	191	0.2	0.12	0.11	0.14	3302	3.6	0.84	0.81	0.87
	2500–2999	271661	2829	1.0	0.85	0.82	0.89	3579	1.3	0.45	0.44	0.47	1343	0.5	0.38	0.36	0.41	1178	0.4	0.23	0.22	0.25	7915	2.9	0.64	0.63	0.66
	3000–3499	845937	8638	1.0	0.83	0.81	0.86	16106	1.9	0.66	0.65	0.68	6710	0.8	0.64	0.62	0.67	7351	0.9	0.50	0.49	0.52	27869	3.3	0.75	0.73	0.76
	3500–3999	957654	11706	1.2	1	Ref		26825	2.8	1	Ref		11114	1.2	1	Ref		14538	1.5	1	Ref		41202	4.3	1	Ref
	4000–4499	415535	6669	1.6	1.32	1.28	1.36	17389	4.2	1.56	1.52	1.59	6934	1.7	1.69	1.63	1.75	10539	2.5	1.98	1.92	2.03	22974	5.5	1.32	1.29	1.34
	4500–4999	83839	1727	2.1	1.71	1.62	1.80	4784	5.7	2.22	2.15	2.29	1845	2.2	2.59	2.46	2.73	3245	3.9	3.61	3.46	3.76	5886	7.0	1.75	1.70	1.80
	≥5000	10717	244	2.3	1.93	1.70	2.20	701	6.5	2.73	2.53	2.94	273	2.5	3.43	3.03	3.89	555	5.2	5.78	5.26	6.35	933	8.7	2.29	2.14	2.45
Fetal sex ^a	Girl	1300887	18026	1.4	1	Ref		35733	2.7	1	Ref		13901	1.1	1	Ref		16634	1.3	1	Ref		54477	4.2	1	Ref
Fetal sex ^a	Boy	1375459	15225	1.1	0.80	0.78	0.82	34722	2.5	0.92	0.90	0.93	14563	1.1	0.99	0.97	1.01	20962	1.5	1.18	1.16	1.21	55601	4.0	0.96	0.95	0.97
Placental weight (grams) ^b	<500	92475	3759	4.1	2.03	1.95	2.11	2361	2.6	0.72	0.68	0.75	1223	1.3	0.74	0.80	0.75	1175	1.3	0.52	0.48	0.55	5623	6.1	0.89	0.87	0.92
	500–699	488935	9892	2.0	1	Ref		17118	3.5	1	Ref		8319	1.7	1	Ref		10732	2.2	1	Ref		31685	6.5	1	Ref
	700–899	328966	6216	1.9	0.93	0.90	0.96	17552	5.3	1.55	1.51	1.59	7201	2.2	1.42	1.37	1.48	13355	4.1	2.07	2.02	2.12	27784	8.4	1.37	1.34	1.39
	900–1099	64314	1451	2.3	1.12	1.06	1.19	4995	7.8	2.32	2.24	2.40	1837	2.9	2.01	1.89	2.13	4175	6.5	3.74	3.60	3.89	6751	10.5	1.78	1.73	1.83
	≥1100	9934	270	2.7	1.37	1.21	1.54	933	9.4	2.85	2.65	3.06	336	3.4	2.59	2.28	2.94	746	7.5	4.62	4.26	5.00	1245	12.5	2.20	2.07	2.34
Velamentous cord insertion ^c	No	992869	21427	2.2	1	Ref		42830	4.3	1	Ref		18809	1.9	1	Ref		30159	3.0	1	Ref		73055	7.4	1	Ref
Velamentous cord insertion ^c	Yes	14907	1006	6.7	3.00	2.79	3.21	828	5.6	1.26	1.17	1.36	356	2.4	1.21	1.07	1.37	517	3.5	0.99	0.90	1.09	1336	9.0	1.24	1.17	1.31
Marginal umbilical cord insertion ^c	No	953165	20948	2.2	1	Ref		40821	4.3	1	Ref		17907	1.9	1	Ref		28818	3.0	1	Ref		70568	7.4	1	Ref
Marginal umbilical cord insertion ^c	Yes	54611	1485	2.7	1.26	1.19	1.33	2837	5.2	1.24	1.19	1.29	1258	2.3	1.25	1.17	1.33	1858	3.4	1.12	1.06	1.18	3823	7.0	1.03	0.90	1.06

CI confidence interval, aOR: OR adjusted for maternal age, parity and period (1967–1977, 1978–1987, 1988–1997, 1998–2007 and 2008–2017).

^a 71 newborns with unknown sex. The negative association with PPH due to trauma or laceration disappeared after adjusting for unmeasured confounder or stratification by preterm/term delivery.

^b 1999–2017, 23152 without placental weight.

^c 1999–2017.