Table 1. Unadjusted Odds Ratios for Associations between Risk Factors and CP, Prematurity, and LBW.

	CP	Prematurity	LBW
Sex
Male	1.00	1.00	1.00
Female	0.80 (0.76–0.83)	1.12 (1.10–1.14)	0.93 (0.91–0.95)
Income groups
1st group	1.00	1.00	1.00
2nd group	0.74 (0.68–0.81)	1.11 (1.08–1.15)	1.07 (1.02–1.11)
3rd group	0.78 (0.72–0.84)	1.12 (1.09–1.16)	1.13 (1.09–1.17)
4th group	0.78 (0.73–0.84)	1.08 (1.05–1.11)	1.12 (1.08–1.16)
5th group	0.86 (0.80–0.93)	1.04 (1.01–1.07)	1.08 (1.04–1.12)
Birth region
Capital (Seoul)	1.00	1.00	1.00
Six metropolitan cities	0.96 (0.89–1.02)	0.97 (0.95–0.996)	0.88 (0.80–0.86)
Small cities	0.97 (0.92–1.03)	1.04 (1.01–1.06)	0.95 (0.93–0.98)
Coverage classification
Self-employed insured	1.00	1.00	1.00
Employee insured	0.99 (0.94–1.05)	1.04 (1.03–1.07)	1.02 (1.001–1.05)
Medical aid	2.64 (2.35–2.97)	0.76 (0.71–0.80)	0.67 (0.63–0.72)

CP, cerebral palsy; LBW, low birth weight.

Data are odds ratio (95% confidence interval).