Table 2.

ORs and 95% CI of GDM risk associated with early pregnancy folic acid supplementation.

	Model	OR (95% CI)	p Value
Total GDM (n = 6396)	1	0.82 (0.70~0.95)	0.009
	2	0.82 (0.71~0.96)	0.012
	3	0.86 (0.74~1.01)	0.063
FBG diagnosed GDM (n = 2154)	1	1.00 (0.79~1.25)	0.965
	2	1.05 (0.82~1.34)	0.706
	3	1.13 (0.88~1.46)	0.327
1-h PBG diagnosed GDM (n = 3920)	1	0.80 (0.67~0.95)	0.012
	2	0.81 (0.68~0.96)	0.017
	3	0.86 (0.72~1.03)	0.101
2-h PBG diagnosed GDM (n = 3857)	1	0.71 (0.60~0.85)	<0.001
	2	0.72 (0.60~0.85)	<0.001
	3	0.75 (0.63~0.90)	0.002

Abbreviations: GDM, gestational diabetes mellitus; FBG, fasting blood glucose; PBG, postprandial blood glucose; OR, odds ratio; CI, confidence interval. Model 1: univariate model; Model 2: not adjust age and pre-pregnancy BMI; Model 3: adjust age, pre-pregnancy BMI, gravidity, parity, smoking history, drinking history, multiple pregnancies, and macrosomia history.