Variable	Group	Subject		Control		Result of the test
Variable	Group	Number	Percent	Number	Percent	Result of the test
Year of delivery	2008	28	24.8	76	23.2	X² = 6.19 P-value = 0.892
	2009	33	29.2	90	27.5
	2010	29	25.7	83	25.4
	2011	23	20.4	78	23.9
Age at the time of delivery	≤18	5	4.4	26	8	X² = 1.631 P-value = 0.442
	18 - 34	83	73.5	234	71.6
	≥35	25	22.1	67	20.5
Place of living	City	94	83.2	249	76.1	X² = 2.241 P-value = 0.120
Place of living	Town/village	19	16.8	78	23.9	X² = 2.241 P-value = 0.120
Place of delivery	Home	2	2.3	1	0.3	Fisher exact test P-value = 0.289
	On the way	1	1.1	7	2.1
	Delivery facilities	0	0	1	0.3
	Hospital	84	96.6	318	97.2
Kind of hospital	Treatment-teaching	43	51.2	122	38	X² = 8.520 P-value = 0.036
	Treatment	21	25	120	37.4
	Private	15	17.9	43	13.4
	Social	5	6	36	11.2
Educational level of the mother	Illiterate	16	14.2	6	1.8	X² = 35.002 P-value < 0.007
	Elementary	16	14.2	22	6.7
	Secondary	22	19.5	85	26
	Diploma	44	38.9	167	51.1
	Higher	15	13.3	47	14.4
Husband’s educational level	Illiterate	13	11.5	9	2.8	X² = 37.626 P-value < 0.001
	Elementary	14	12.4	16	4.9
	Secondary	29	25.7	54	16.5
	Diploma	41	36.3	188	57.5
	Higher	16	14.2	60	18.3
Health insurance	Yes	78	69	208	63.6	X² = 1.084 P-value = 0.298
Health insurance	No	35	31	119	36.4	X² = 1.084 P-value = 0.298
Type of Citizenship	Iranian	99	87.6	280	85.6	X² = 0.277 P-value = 0.599
Type of Citizenship	Non-Iranian	14	12.4	47	14.4	X² = 0.277 P-value = 0.599
Immigration certificate	Yes	5	35.7	21	45.7	X² = 0.432 P-value = 0.511