Table 4.

Adjusted odds ratios for LBW infants by socioeconomic level among women of Mexico City

Variable	Model 1		Model 2		Model 3
	OR	95% CI	OR	95% CI	OR	95% CI
Socioeconomic level
Medium	1.14	[0.75,1.74]	1.16	[0.76,1.77]	1.12	[0.72,1.74]
Low	2.57	[1.19,5.58]	2.45	[1.13,5.36]	2.68	[1.19,6.03]
Maternal age (years)
<19	0.74	[0.43,1.25]	0.74	[0.43,1.26]	0.57	[0.32,1.03]
>30	1.17	[0.70,1.98]	1.09	[0.64,1.84]	1.34	[0.76,2.38]
Maternal education (years)
< 7	1.21	[0.58,2.56]	1.11	[0.52,2.40]	1.05	[0.47,2.34]
7–9	1.29	[0.63,2.62]	1.23	[0.59,2.55]	1.39	[0.66,2.94]
10–12	1.56	[0.78,3.13]	1.61	[0.79,3.27]	1.82	[0.87,3.77]
Unmarried	0.99	[0.49,2.01]	1.08	[0.52,2.28]	0.96	[0.44,2.08]
No accessibility to public services	0.68	[0.34,1.33]	0.58	[0.29,1.17]	0.56	[0.27,1.14]
Smoking before pregnancy			0.99	[0.57,1.72]	1.07	[0.60,1.90]
Smoking during pregnancy			1.09	[0.43,2.78]	1.14	[0.43,2.99]
Hypertension			1.61	[0.95,2.73]	1.55	[0.90,2.68]
Urinary tract infection			1.23	[0.83,1.83]	1.14	[0.76,1.71]
No calcium supplementation			1.98	[1.01,3.87]	2.30	[1.14,4.63]
No iron supplementation			1.23	[0.84,1.80]	1.32	[0.89,1.96]
No prenatal care			1.15	[0.47,2.87]	1.27	[0.52,3.19]
Primiparous					1.73	[1.05,2.83]
Pre-gestational weight(kgs)
<48					2.33	[1.33,4.08]
49–54					1.28	[0.71,2.31]
>60					1.32	[0.74,2.36]
Previous preterm birtha					2.95	[1.04,8.38]**
Previous low birth weighta					2.61	[1.36,5.04]
Previous abortiona					0.52	[0.17,1.63]

^aonly applicable for women with more than one pregnancy.