Table 1

Characteristics of included studies (in chronological order)
First author, year, Setting/Location Participants, Recruitment Interventions, No. of subjects Methods Outcomes Duration of intervention Potential risk of bias rating
Bailey 1983[48] 101 pregnant women aged 15–41 years 1. Standard WIC program- Monthly vouchers for specified quantities of milk, canned fish, carrots, cereal, cheese, eggs. 6 monthly nutrition education and health care referrals n=43 Controlled before and after study Serum iron, vitamin B6, folic acid, 12 weeks High
WIC clinic and hospital prenatal clinic, Florida, USA WIC and control participants recruited from different prenatal clinics at 30 weeks gestation Red cell folate
2. Routine antenatal care through hospital clinic n=58 Follow-up period 12 weeks Dietary iron, vitamin B6, and folic acid
Birth weight
% Low birth weight
Metcoff 1985[42] 824 pregnant women stratified by predicted birth weight; all WIC eligible 1.Standard WIC program with research assessments and routine prenatal care n=238 Randomised controlled trial Birth weight ~21 weeks High
Plasma B-carotene
Hospital prenatal clinic, Oklahoma City, Oklahoma, USA Maternal weight
All participants recruited from same hospital prenatal clinic 2. Routine prenatal care with research assessments n=172 Follow-up period 24 weeks Plasma amino acids
3. Routine prenatal care n=353
Caan 1987[38] 703 post-partum women- all WIC participants prenatally 1. Standard WIC program maintained for 6 months post-partum for non-lactating women n=333 Controlled before and after study Birth weight 6 months High
Low birth weight
Macrosomia
48 local WIC agencies, California, USA All WIC participants prenatally, divided into control &intervention groups retrospectively based on WIC benefits post-partum 2. Standard WIC entitlement for 0–2 months post-partum n=309 Maternal Hb
Follow-up period-duration of prenatal care in second pregnancy Maternal BMI
Rush 1988a[44] 11,154,673 pregnant women from 1392 US counties in 19 states 1. Standard WIC program Interrupted time series Birth weight Duration of prenatal WIC participation Low
Duration of gestation
National sample of counties, USA WIC participants increased over time from 0 to 39% from government reports Follow-up period 1972-1981 Fetal mortality (>28 weeks)
Infant mortality rate
Inadequate prenatal care
Rush 1988b&c[45,47] 6563 pregnant women, all WIC eligible by income 1. Standard WIC program and research assessments n=5205 Controlled before and after study Nutrient intake Duration of prenatal WIC participation High
174 WIC clinics and 55 prenatal clinics, national sample, USA WIC participants recruited at WIC clinics, controls recruited at public prenatal clinics in counties with low WIC coverage 2. Routine antenatal care and research assessments n=1358 Follow-up period 6–9 months
Mean nutrient intake % RDA
Anthropometry
Duration of gestation
Birth weight
Fetal mortality
Rush 1988c&d[45,46] 5004 pregnant women, mean age 22.4 years 1. Standard WIC program n=4219 Controlled before and after study Family food expenditure Duration of prenatal WIC participation High
174 WIC clinics and 55 prenatal clinics, national sample, USA 2. Routine antenatal care n=785 Family grocery expenditure
WIC participants recruited at WIC clinics, controls recruited at public prenatal clinics in counties with low WIC coverage A subset of women were asked to complete a food diary at follow-up: WIC n=1031, Control n=551 Follow-up period 6–9 months Family meals out expenditure
Gunnell 2000[39] 1089 children aged 2–14 years, mean age 8 years 1. Daily school feeding soup/milk, halibut oil capsules, oranges or milk and marmite n=298 Controlled before and after study Height 12 months Moderate
Leg length
8 rural and urban locations in Scotland and England, UK Disadvantaged families selected and divided into intervention and control groups arbitrarily
2. Family food packages weekly-milk, cheese, wheat germ, marmite, oranges, cod liver oil, eggs n=269 Follow-up period 13 months for children′s growth and 60 years for mortality Mortality
School in adjacent areas were also selected as intervention and controls non-randomly 3. No food subsidy- control families n=261
4. No food subsidy- control schools n=258
Pehrsson 2001[43] 110 post-partum non-lactating females >18 years old, all WIC participants prenatally 1. Standard WIC program for 6 months post-partum n=57 Controlled before and after study Haemoglobin 6 months Low
Transferrin receptor
Urban WIC clinics, Maryland, USA Participants recruited at WIC clinics in different counties 2. Standard WIC program for 0–2 months post-partum n=53 Follow-up period 6 months Anaemia %
Ferritin
Burr 2007[37] 190 pregnant females aged >=17 yo 1. Vouchers for free 2L fruit juice weekly (home delivery) n=63 Randomised controlled trial Frequency of specific fruit consumption Throughout prenatal care period (~30 weeks) High
District hospital prenatal clinic, Wales, UK (disadvantaged area) All participants recruited from one hospital prenatal clinic at booking visit 2. Advice/written information from midwives to promote fruit intake during pregnancy n=63 Follow-up period 30 weeks Serum β-carotene
3. Routine antenatal care n=64
Herman 2006 & 2008[32,40] 602 post-partum women >18yo- all WIC participants 1. $10 voucher weekly for F&V at local supermarket plus standard WIC program n=200 Controlled before and after study F&V intake 6 months High
3 WIC clinics, Los Angeles, California, USA Intervention and control participants recruited at three separate WIC clinics with similar socio-demographics 2. $10 voucher weekly for F&V at local farmers market plus standard WIC program n=200 Follow-up period 1 year
3. Standard WIC program n=202
Currie 2008[49] All pregnant Californian women 1961–1974 n=4864673 1. Standard Food Stamp Program- monthly food vouchers for any foods up to $200/person/month dependent on income and household size Interrupted time series Median birthweight Duration of prenatal FSP participation Low
Low birthweight rate
California, USA Food stamp participation rates by county used to calculate impacts Follow-up period 1961-1974 Probability of birthweight <specified cut-off
Hoynes 2009[18] 28,000,000 pregnant women in the 2059 US counties with a WIC program by 1979 (85% of US births in the 1970s) 1. Standard WIC program Interrupted time series Birth weight Duration of prenatal WIC enrolment Low
National sample of counties, USA Follow-up period % Low birth weight
WIC participation estimated from government reports 1971-75 & 1978-82
Kennedy 2009[41] 40 African-American women aged >18yrs, non-pregnant 1. F&V $10/week with recipes from mobile store at community centre, monthly nutrition education, cooking demonstrations and anthropometric assessment n=20 Randomised controlled trial Fruit and vegetable consumption 6 months High
Community centre, East Baton Rouge, Louisiana, USA Participants recruited by local community advertising and personal communication 2. Monthly anthropometric assessment and written nutrition education n=20 Follow-up period 6 months Weight
BMI
BP
Quality of life
General and emotional health
Ni Mhurchu 2010[30] 1104 adult >18 years, main household shopper, 86% female 1. Tailored nutrition education– computer-generated messages and shopping lists plus generic recipes monthly by mail n=274 Randomised controlled trial Total food purchased 6 months Low
8 supermarkets in Wellington, Wanganui and New Plymouth, NZ Follow-up period Healthy food purchased
Participants recruited by mail invitation, supermarket advertisements and community group promotion (for Maori and Pacific communities) 2. Price discount of 12.5% on healthy foods applied automatically at check-out n=275
15 months Less healthy food purchased
F&V purchased
3. Price discount plus tailored nutrition education n=277 Macronutrients purchased
4. Control n=278

Black et al.

Black et al. BMC Public Health 2012 12:1099   doi:10.1186/1471-2458-12-1099

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