Table 2.

Multivariate analysis of socio-demographic factors affecting pre-pregnancy BMI values

	OR (95% CI)	P-value
<  20 vs 20 ~ 25	1.97 (1.20–3.25)	0.008
25 ~ 30 vs 20 ~ 25	1.66 (1.26–2.19)	<  0.001
30 ~ 35 vs 20 ~ 25	2.24 (1.67–2.99)	<  0.001
35 ~ 40 vs 20 ~ 25	3.90 (2.75–5.54)	<  0.001
≥ 40 vs 20 ~ 25	3.33 (1.87–5.92)	<  0.001
Elementary school or below vs college or university	3.53 (1.43–8.75)	0.006
Middle school vs college or university	1.53 (1.22–1.92)	<  0.001
High school vs college or university	1.40 (1.15–1.72)	0.001
Postgraduate degree vs college or university	0.84 (0.61–1.16)	0.299
PhD degree vs college or university	0.34 (0.12–1.02)	0.054
North vs South	1.37 (1.16–1.62)	<  0.001