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Table 1
Basic characteristics of included studies
Study	Participant characteristics			Short description of intervention	Total folate intake^*(μg/day)	Mean duration of intervention^**	Health outcomes
	Country	Age	No. in intervention and control groups
Baumslag 1970 [25]	South Africa	N/A	65; 63^a and 62; 52^b	200 mg iron + 5 mg FA/day	8620^a; 8747^b	16 wk^a and 12 wk^b	birth weight
				200 mg iron/day	120^a; 247^b
Iyengar 1971 [26]	India	N/A	23; 26	60 mg iron + 300 μg FA/day	757	18 wk	birth weight
				60 mg iron/day	247
Iyengar 1975 [27]	India	N/A	98; 91	60 mg iron + 500 μg FA/day	1097	16 wk	birth weight; placental weight
				60 mg iron/day	247
Klingler 2006 [24]	Spain	18-40 y	16; 12	400 μg 5-MTHF/day	647	20 wk	birth weight; placental weight; length of gestation
			11; 16	placebo/day	247
				fish oil + 400 μg 5- MTHF/day	647
				fish oil/day	247
Lira 1989 [19]	Chile	26.8±4.3 y 26.6±5.3 y	75; 78	105 mg iron + 350 μg FA/day	842	24 wk	length of gestation
				105 mg iron/day	247
Nogueira 2002 [23]	Brasil	13-18 y	15; 13	120 mg iron sulphate + 250 μg FA/day	545	22 wk	birth weight; length of gestation
				120 mg iron sulphate/day	120
Rolschau 1979 [33]	Denmark	N/A	20; 16	250 mg ferrofumarate + 5 mg FA/day	8747	17 wk	birth weight; placental weight; length of gestation
				250 mg ferrofumarate/day	247
Tchernia 1982 [28]	France	N/A	54; 54	iron + μg FA/day	842	12 wk	birth weight; placental weight; length of gestation
				iron/day	247

Abbreviations: a, data of Bantu women; b, data of White women; FA, folic acid; 5-MTHF, 5-methyltetrahydrofolate; N/A, data not available; *, expressed as Dietary Folate Equivalents; **, supplements were administered from the second trimester to delivery in each study.

Fekete et al. Nutrition Journal 2012 11:75 doi:10.1186/1475-2891-11-75

Table 1