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Table 1 Characteristics of included studies

From: Systematic review of clinical trials on dietary interventions to prevent excessive weight gain during pregnancy among normal weight, overweight and obese women

Author/year Country Design Population Recruitment Intervention type Description Quality Risk of bias
Asbee, 2009 [18] USA RCT n = 100
All BMI categories (< 40.5 kg/m2), age 18-49 years
wk 6-16 of gestation 1. diet + PA
counseling
2. usual care
Individual session with a dietician only at 1st visit. Diet should consist of 40% CH, 30% protein and 30% fat. GWG monitored at every visit. Moderate exercise 3-5 times/wk. Randomization: A
Allocation: A
Blinding: B
Losses: A
moderate
Badrawi, 1992 [37] Egypt RCT n = 100
Obese multiparous women, age 25-35 years
early in pregnancy 1. caloric
restriction
2. usual care
Usual care: Normal diet according to WHO energy recommendations (2300-3000 kcal/day). Intervention: balanced low-energy diet (1500-2000 kcal/day). Randomization: A
Allocation: B
Blinding: B
Losses: B
moderate
Campbell, 1975 [19] Scotland QCT n = 102
Primiparous women with high GWG (> 570 g/wk) at 20-30 weeks gestation
wk 30 of gestation 1. caloric
restriction
2. usual care
3. diuretics*
A low-energy diet (1200 kcal/day) with low CH. The second intervention group was excluded, due to use of drugs as part of the intervention. Randomization: B
Allocation: C
Blinding: B
Losses: B
high
Campbell 1982 [38] Scotland QCT n = 182
Obese primiparous
women
wk 29-30 of
gestation
1. caloric
restriction
2. usual care
A low-energy diet (1250 kcal/day), instructed by a dietitian at recruitment Randomization: B
Allocation: C
Blinding: B
Losses: B
high
Guelinckx, 2009 [20] Belgium RCT n = 122
White, obese
pregnant women,
BMI > 29
< wk 15 of gestation 1. brochure
2. brochure +
diet + PA
counseling
3. usual care
Intervention 1: Given a purpose design brochure at 1st prenatal consultation, with nutritional and PA advice to limit GWG according to IOM guidelines. Intervention 2: Brochure + active lifestyle education by a nutritionist in 3 1 hour group sessions. All participants: Nutritional habits evaluated every trimester with three 7-day food records. Randomization: A
Allocation: A
Blinding: C
Losses: C
high
Huang, 2009 [21] Taiwan RCT n = 125
Pregnant women
≥ 18 years of age
< 16 wk of
gestation
1. diet + PA
counseling +
brochure during
pregnancy
2. diet + PA
counseling +
brochure given
postpartum*
3. usual care
Usual care: Routine obstetric educational program, once each trimester. Intervention 1: 6 individual session with a dietician with individualized diet and PA plan + brochure, from recruitment to 6 months post partum. Randomization: A
Allocation: A
Blinding: A
Losses: C
high
Hui, 2006 [39] Canada RCT n = 45
Pregnant women with no preexisting diabetes
< 26 wk of
gestation
1. diet + PA
counseling
2. usual care
Usual care: information package on diet and PA for a healthy pregnancy. Intervention: Group and home based exercises (3-5 times/wk for 30-45 min was recommended). They also received Computer assisted Food Choice Map, dietary interviews and counseling. Randomization: A
Allocation: B
Blinding: B
Losses: A
moderate
Ilmonen, 2010 [22] Finland RCT n = 171 < 17 wk of gestation 1. diet + placebo
2. diet + probiotics*
3. usual care + placebo
Intervention groups: Dietary counseling (nutritionist) + probiotic or placebo capsules and food products for home use, each trimester and at 1, 6 and 12 months post partum. Diet should consist of 55-60% CH, 10-15% protein and 30% fat. Randomization: A
Allocation: A
Blinding: A
Losses: C
high
Kinnunen, 2007 [23] Finland QCT n = 105
Normal weight primiparous women ≥ 18 years
< 8-9 wk of gestation 1. diet + PA
counseling
2. usual care
Usual care: Primiparas are recommended 11-15 visits to a public health nurse and 3 to a physician during pregnancy. Intervention: Individual counseling on diet + PA and IOM guidelines for GWG, during 5 routine visits to a public health nurse from wk 8-9 to wk 37 of gestation. Option to attend supervised group exercise. Randomization: D
Allocation: B
Blinding: B
Losses: C
high
Phelan, 2011 [24] USA RCT n = 358
Non-smoking pregnant women, BMI 19,8-40
wk 10-16 of gestation 1. diet + PA
counseling
2. usual care
Intervention: Standard care + 1 visit to interventionist promoting self monitoring including; appropriate weight gain, PA (30 min/day) and diet (20 kcal/kg). Participants also received 3 phone calls from a dietitian + weekly mail. Randomization: A
Allocation: A
Blinding: A
Losses: A
low
Polley, 2002 [25] USA RCT n = 110
Normal weight pregnant women, BMI 19,8-26
Overweight pregnant women, BMI > 26
< 20 wk of gestation 1. diet + PA
counseling
2. usual care
Intervention: Regularly antenatal visits with access to research dietician and psychologist. Newsletters and phone calls between clinical visits, with education and feedback relating to weight gain, exercise and healthy eating. Randomization: A
Allocation: B
Blinding: B
Losses: A
Moderate
Thornton, 2009 [26] USA RCT n = 232
Obese pregnant women, BMI ≥ 30
wk 12-28 of gestation 1. caloric
restriction
2. usual care
Intervention: Placed on an 18-24 kcal/kg diet consisting of 40% CH, 30% protein, and 30% fat after a visit to a dietitian. The women were asked to record in a diary all of the foods and beverages consumed during each day. Randomization: A
Allocation: A
Blinding: B
Losses: A
moderate
Wolf, 2008 [27] Denmark RCT n = 50
Caucasian obese pregnant women, BMI ≥ 30
wk 15-18 of gestation 1. caloric
restriction
2. usual care
Intervention: Restriction of GWG to 6-7 kg by 10 1-hour dietary consultations with a trained dietitian, at each antenatal visit. Individual recommendation on daily energy intake, coming from 50-55% CH, 15-20% protein and max 30% fat, according to the official Danish dietary recommendations. 7 day weighed food records were used and individualized suggestions of improvement, were given to those with an identified unhealthy eating pattern. Randomization: A
Allocation: B
Blinding: A
Losses: C
high
  1. BMI - body mass index, CH - carbohydrates, GWG - gestational weight gain, min - minutes, PA - physical activity, QCT - quasi-randomized controlled trial, RCT - randomized controlled trial, wk - week
  2. * Comparison group not considered in this review