Table 4. Characteristics of included studies.

Study	Participants	Intervention	Comparison	Outcome measures	Results/Conclusion
Polley et al. [54]	120 pregnantwomen at<20 weeksgestation	Single, standardised, one-to-onediet and lifestyle counsellingsessions. Weekly mailed writtenmaterial. Regular weightmonitoring. Supportivetelephone calls.	StandardAntenatal Care	GWG above IoM guidelines	Intervention group had a significantly lower number of NW women exceeding IoM guidelines vs. control group. No significant improvements in GWG for OW/OB women.
Asbee et al. [55]	100 pregnantwomen, at6–16 weeksgestation	One-to-one, standardiseddietary and lifestyle counselling.Instructed to engage inmoderate-intensity exerciseat least 3 times per week.Regular weight monitoring.	StandardAntenatal Care	GWG within the IoM guidelines.	Intervention group gain significantly less weight than the control group. No statistically significant differences between groups in the adherence to IoM guidelines.
Huang et al. [56]	189 pregnantwomen<16 weeksgestation	Six, individualised, one-to-onediet and lifestyle counsellingsessions. Regular weightmonitoring. Researcher-preparedbrochure.	StandardAntenatal Care	Body weight changes.Psycho-social variablessuch as; health-promoting behaviour,self-efficacy, bodyimage, depression,social support.	All outcome indicators were significantly better for intervention group vs. control group.
Phelan et al. [57]	401 pregnantwomen between10 and 16 weeksgestation	Single, standardised, one-to-onediet and lifestyle counsellingsession. Weekly mailed materials.Regular weight monitoring.Supportive telephone calls.	StandardAntenatal Care	GWG above IoM guidelines	Intervention group had a significantly lower number of NW women exceeding IoM guidelines vs. control group. No significant improvements in GWG for OW/OB women.
Wolff et al. [58]	50 obese pregnantwomen at∼15 weeksgestation	Ten, individualized, one-to-onedietary counselling sessionsbased on restrictions onenergy intake.	Standardantenatal care	Weightdevelopment	Intervention group gained significantly less weight than the control group.

Abbreviations: GWG, gestational weight gain; IoM, Institute of Medicine; NW, normal weight; OW, overweight; OB, obese.