Table 5.

Associations of folate acid supplementation and dietary folate intake with the risk of nulliparous-LBW and multiparous-LBW.

Folic acid/folate intake duration	NBW (n= 8581)	Nulliparous –LBW		Multiparous -LBW
		Cases(n= 374)	ORc (95% CI)	Cases(n= 276)	ORc (95% CI)
Folic acid supplement
Nonusers	1859	122	1.00	117	1.00
Users	6722	252	0.88 (0.68~1.13)	159	0.72 (0.54~0.94)
≤ 12 weeks	3500	154	0.90 (0.69~1.18)	108	0.77 (0.58~1.04)
>12 weeks	3222	98	0.94 (0.80~1.10)	51	0.74 (0.61~0.89)
P for trend			<0.001		<0.001
Before conception and during pregnancy	2542	88	0.98 (0.70~1.38)	41	0.55 (0.36~0.83)
<24 weeks	1179	49	1.01 (0.68~1.50)	26	0.67 (0.42~1.07)
≥24 weeks	1363	39	0.98 (0.78~1.22)	15	0.61 (0.45~0.83)
P for trend			0.020		<0.001
Before conception only	326	12	0.85 (0.45~1.62)	7	0.57 (0.26~1.27)
During pregnancy only	3854	152	0.88 (0.67~1.15)	111	0.76 (0.57~1.02)
<12 weeks	1656	79	0.90 (0.66~1.24)	59	0.79 (0.56~1.12)
≥12 weeks	2198	73	0.90 (0.76~1.06)	52	0.82 (0.68~0.98)
P for trend			0.008		<0.001
Dietary folate intake (μg/day)
Before pregnancy
Q1 <116.01	2090	123	1.00	95	1.00
Q2 116.01–158.54	2186	75	0.69 (0.50~0.95)	51	0.74 (0.50~1.09)
Q3 158.54–220.88	2134	98	1.01 (0.87~1.18)	70	1.04 (0.87~1.24)
Q4 ≥220.88	2171	78	0.90 (0.79~1.03)	60	1.05 (0.90~1.22)
P for trend			0.171		0.894
During pregnancy
Q1 <149.81	2086	117	1.00	107	1.00
Q2 149.81–197.59	2125	87	1.00 (0.73~1.39)	64	0.96 (0.67~1.38)
Q3 197.59–263.67	2144	91	1.02 (0.86~1.22)	47	0.86 (0.70~1.06)
Q4 ≥263.67	2226	79	1.01 (0.87~1.18)	58	1.03 (0.87~1.23)
P for trend			0.308		0.135

^ORcadjusted for maternal age, education level, monthly income per capita, smoking, employment, weight gain during pregnancy, preeclampsia, cesarean section, total energy intake, dietary folate intake, or folic acid supplement.