Table 3.

Univariable analysis of maternal serum vitamin D levels and common adverse pregnancy outcomes.

	Maternal vitamin D status during pregnancy
	Deficiency	Insufficiency	Sufficiency	P Deficiency VS Sufficiency	P Insufficiency VS Sufficiency
Gestational diabetes
Total number of pregnant women	2565	473	42
Pregnant women with gestational diabetes	209	47	4
RR/95% CI for gestational diabetes	0.84 (0.298∼2.384)	1.05 (0.358∼3.066)	1.00	.747	.932
Hypertension-related diseases
Pregnant women with hypertension-related diseases	192	32	4
RR/95% CI for hypertension-related diseases	0.77 (0.271∼2.176)	0.69 (0.232∼2.052)	1.00	.619	.502
Premature rupture of membranes
Pregnant women with premature rupture of membranes	498	83	7
RR/95% CI for premature rupture of membranes	1.21 (0.532∼2.728)	1.06 (0.457∼2.478)	1.00	.655	.885
Cesarean section
Pregnant women with cesarean section	1202	239	22
RR/95% CI for cesarean section	0.80 (0.435∼1.476)	0.93 (0.494∼1.747)	1.00	.477	.818
Premature birth
Pregnant women with premature birth	195	20	1
RR/95% CI for premature birth	3.37 (0.462∼24.656)	1.81 (0.237∼13.833)	1.00	.203	.562
Spontaneous abortion
Pregnant women with spontaneous abortion	402	18	1
RR/95%CI for spontaneous abortion	7.62 (1.045∼55.554)	1.62 (0.211∼12.460)	1.00	.018∗	.639