Table 1 Characteristics of included studies

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 1^st 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 1^st 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