Stress, Violence, Depression, and Low Social Support and Their Association with Preterm Birth in a Brazilian Cohort

Table 1

Demographic characteristics, obstetric history, and data related to stress, violence, and social support of the women studied regarding the outcome (presence or absence of preterm birth) and risk factors for preterm birth in univariate analysis.

Variable	Spontaneous preterm birth				95% CI
	No ()	Yes ()	Total ()	Unadjusted RR	LL	UL
	(%)	(%)	(%)
Age (years)
<18	99 (8)	9 (6.77)	108 (7.9)	0.87	0.45	1.67
18–35	1,053 (85.13)	111 (83.46)	1164 (85)	Ref	Ref	Ref
>35	85 (6.87)	13 (9.77)	98 (7.1)	1.39	0.81	2.37
Education
Incomplete elementary school	197 (15.98)	27 (20.30)	224 (16.4)	1.33	0.67	2.66
Complete elementary school	935 (75.83)	96 (72.18)	1031 (75.5)	1.03	0.55	1.92
Complete high school and/or higher	101 (8.19)	10 (7.52)	111 (7.1)	Ref	Ref	Ref
Household income
<2 MW	343 (30.68)	38 (31.67)	381 (30.8)	0.923	0.349	2.442
2 to 10 MW	742 (66.37)	78 (65.00)	820 (66.2)	0.880	0.341	2.273
>10 MW	33 (2.95)	4 (3.33)	37 (3)	Ref	Ref	Ref
Partner
No	229 (18.54)	33 (24.81)	262 (19.1)	1.39	0.96	2.01
Yes	1,006 (81.46)	100 (75.19)	1106 (80.9)	Ref	Ref	Ref
Alcohol consumption
No	927 (75.18)	94 (70.68)	1021 (74.7)	Ref	Ref	Ref
Yes	306 (24.82)	39 (29.32)	345 (25.3)	1.22	0.86	1.74
Smoking
No	1,083 (87.83)	107 (80.45)	1190 (87.1)	Ref	Ref	Ref
Yes	150 (12.17)	26 (19.55)	176 (12.9)	1.64	1.10	2.44
Illicit drug use
No	1,174 (95.76)	129 (97.73)	1303 (95.9)	Ref	Ref	Ref
Yes	52 (4.24)	3 (2.27)	55 (4.1)	0.55	0.18	1.67
Parity
1	617 (49.88)	59 (44.36)	676 (49.3)	Ref	Ref	Ref
2	362 (29.26)	39 (29.32)	401 (29.3)	1.11	0.75	1.63
3 or more	258 (20.86)	35 (26.32)	293 (21.4)	1.36	0.92	2.03
History or preterm birth
No	1,132 (91.88)	118 (89.39)	1250 (91.6)	Ref	Ref	Ref
Yes	100 (8.12)	14 (10.61)	114 (8.4)	1.30	0.77	2.18
Stress
Mild	423 (34.2)	33 (24.81)	456 (33.3)	Ref	Ref	Ref
Moderate	419 (33.87)	40 (30.08)	459 (33.5)	1.20	0.77	1.87
Severe	395 (31.93)	60 (45.11)	455 (33.2)	1.82	1.21	2.73
Number of stressful life events
None	460 (37.19)	41 (30.83)	501(36.5)	Ref	Ref	Ref
1 or 2	598 (48.34)	64 (48.12)	662 (48.3)	1.18	0.81	1.71
3 or more	179 (14.47)	28 (21.05)	207 (15.1)	1.65	1.05	2.59
General violence
No	678 (54.81)	74 (55.64)	752 (54.9)	Ref	Ref	Ref
Yes	559 (45.19)	59 (44.36)	618 (45.1)	0.97	0.70	1.34
Psychological violence
No	692 (55.94)	75 (56.39)	767 (56)	Ref	Ref	Ref
Yes	545 (44.06)	58 (43.61)	603 (44)	0.98	0.71	1.36
Physical violence
No	1,084 (87.63)	116 (87.22)	1200 (87.6)	Ref	Ref	Ref
Yes	153 (12.37)	17 (12.78)	170 (12.4)	1.03	0.63	1.67
Sexual violence
No	1,189 (96.12)	129 (96.99)	1318 (96.2)	Ref	Ref	Ref
Yes	48 (3.88)	4 (3.01)	52 (3.8)	0.78	0.30	2.04
Depression
Irrelevant symptoms	628 (50.77)	56 (42.11)	684 (50)	Ref	Ref	Ref
Possibly depressed	308 (24.9)	35 (26.32)	343 (25)	1.24	0.83	1.86
Probably depressed	301 (24.33)	42 (31.58)	343 (25)	1.49	1.02	2.18
Social support
Low	411 (33.23)	46 (34.59)	457 (33.4)	Ref	Ref	Ref
Medium	413 (33.39)	43 (32.33)	456 (33.2)	0.93	0.63	1.39
High	413 (33.39)	44 (33.08)	457 (33.4)	0.95	0.64	1.41

MW: minimum wage (US$ 267.81); : sample number; RR: relative risk; LL: lower limit; UL: upper limit.