Table 1.

Risk factors in women with and without PAS (univariate logistic regression models)

Characteristics	Univariate
	Class	Control (no PAS) n=552	Case (PAS) n=187	OR	95% CI	p-value
		N (%)	N (%)
Maternal age (year)	Mean±SD	28.76±6.33	32.79±4.84	1.120	1.086–1.154	<0.001
Parity
	<3	472 (85.5)	98 (52.4)	Ref	-	<0.001
	≥3	80 (14.5)	89 (47.6)	5.358	(3.69–7.77)
Gravidity
	<3	328 (59.4)	24 (12.8)	Ref	-	<0.001
	≥3	224 (40.6)	163 (87.2)	9.945	(6.27–15–76)
History of abortion
	No	446 (80.8)	133 (71.3)	Ref	-	0.006
	Yes	106 (19.2)	54 (28.9)	1.708	(1.16–2.5)
History of curettage
	No	515 (93.3)	153 (81.8)	Ref	-	<0.001
	Yes	37 (6.7)	34 (18.2)	3.093	(1.87–5.09)
Prior cesarean delivery
	No	392 (71.0)	5 (2.7)	Ref	-	<0.001
	Yes	160 (29.0)	182 (97.3)	89.1	(35.99–220.5)
Number of cesarean deliveries
	<3	130 (81.3)	118 (63.4)	Ref	-	<0.001
	≥3	30 (18.8)	68 (36.6)	2.49	(1.52–4.103)
Myomectomy
	No	547 (99.1)	187 (100.0)	Ref	-	0.809
	Yes	5 (0.9)	0 (0.0)	0.82	(0.16–4.24)
History of ectopic pregnancy
	No	548 (99.3)	182 (97.3)	Ref	-	0.036
	Yes	4 (0.7)	5 (2.7)	3.764	(1.00–14)
Infertility treatment
	No	527 (95.5)	183 (97.9)	Ref	-	0.155
	Yes	25 (4.5)	4 (2.1)	0.461	(0.15–1.34)
Smoking
	No	550 (99.6)	186 (99.5)	Ref	-	0.750
	Yes	2 (0.4)	1 (0.5)	1.477	(0.13–16.39)
History of accreta
	No	551 (99.8(	186 (99.5 )	Ref	-	0.443
	Yes	1 (0.2)	1 (0.5)	2.96	(0.18–47.59)
History of previa
	No	550 (99.6)	185 (98.9)	Ref	-	0.287
	Yes	2 (0.4)	2 (1.1)	2.97	(0.41–21.32)
Multiple pregnancy
	No	535 (96.9)	182 (97.3)	Ref	-	0.778
	Yes	17 (3.1)	5 (2.7)	0.86	(0.31–2.37)
Hypertensive disorder
	No	502 (90.9)	173 (92.5)	Ref	-	0.510
	Yes	50 (9.1)	14 (7.5)	0.81	(0.43–1.50)
Diabetes
	No	494 (89.5)	157 (84.0)	Ref	-	0.045
	Yes	58 (10.5)	30 (16.0)	1.40	(1.01–2.62)
Previa
	No	545 (98.7)	128 (68.4)			<0.001
	Yes	7 (1.3)	59 (31.6)	35.88	(16.01–80.4)