Table 2.

Summary of the meta-analysis of associated factors for GDM.

No.	Factors	No. studies included	OR	95% CI	I 2	P heterogeneity	t	Bias P heterogeneity
1	Maternal age ≥ 25 years	36	2.466	2.121, 2.866	96.2	<0.001	0.19	0.243
2	Prepregnancy overweight or obese	48	2.637	1.561, 4.453	99.8	<0.001	4.85	0.001
3	FHD	74	2.326	1.904, 2.843	94.7	<0.001	1.83	0.081
4	Primigravida	56	0.752	0.698, 0.810	94.7	<0.001	1.53	0.132
5	History of congenital anomaly	3	1.837	0.418, 8.067	0.0	0.421	—	—
6	History of GDM	24	21.137	8.785, 50.858	96.9	<0.001	1.35	0.181
7	History of macrosomia	26	2.539	1.612, 4.000	86.6	<0.001	2.24	0.035
8	HIV status	4	1.168	0.902, 1.512	0.0	0.238	—	—
9	History of stillbirth	11	2.341	1.435, 3.819	52.0	0.001	0.18	0.862
10	History of abortion	19	1.546	0.906, 2.639	94.3	0.110	0.26	0.800
11	History of premature delivery	3	3.013	1.569, 5.787	0.0	0.001	—	—
12	Pregestational smoking	9	2.322	1.359, 3.967	66.7	0.002	—	—

CI: confidence interval; FHD: family history of diabetes mellitus; GDM: gestational diabetes mellitus; HIV: human immunodeficiency virus; OR: odds ratio.