Methods	Study design: Randomized controlled trial
	Unit of randomization: Individually randomised
	Type of study: Obesity prevention
Participants	Location/setting: Family healthcare centre, Istanbul, Turkey
	Population: 21 000
	Sample size: 102
	Drop outs/withdrawal: 12 (6 in intervention group, 6 from control) due to miscarriage(2), preterm birth (2) relocation (3) and 5 discontinuations
	Socio‐demographics
	Mean (SD) age/age range: Intervention: 24.31 (4.22) Control: 24.28 (4.15)
	Occupation: Not specified
	Race: Not specified
	Education:
	Intervention: 7.6 ± 3.2
	Control: 6.6 ± 2.8
	Family income:
	Working women n (%)
	Intervention:
	Low: 15 (33.3)
	Middle: 30 (66.7)
	Control:
	Low: 11 (24.4)
	Middle: 34 (75.6)
	Inclusion criteria:
	Pregnant women aged over 18, who had no health problem, did not intend to lose weight in prepregnancy period, got pregnant in natural ways for two times at most, and were pregnant for a period of 3 months or less, were included in the study
	Exclusion criteria: Pregnancy complications, not coming to regular follow‐ups
Interventions	Intervention (sample size):
	Lifestyle intervention for whole pregnancy till 6 weeks postpartum. 4 meetings were held with women regarding healthy lifestyle, nutrition, exercise, and weight follow‐up. Patients were given a card on which weight, height, and gestational weight gain were recorded. The women were provided with praise and those that were not able to meet objectives had their short comings reviewed. Women who could not reach their objectives were given more intensive consultancy (repetition of basic nutrition and physical activity recommendations, reviewing individual objectives, and supportive phone consultancy) was provided. Counselling and behavioral coaching was personalized according to the barriers for individuals. Meetings were supplemented with 15 minute health training and brochures were delivered
	It was delivered by the first author of the study (nurse) (n = 51)
	Control (sample size):
	Standard of care. Consultancies mostly consist of subjects such as pregnancy complaints, scope of antenatal care, tests to be performed, birth, post‐partum period, and circumstances that might pose danger during pregnancy, There is no standard training and consultancy. Women in the standard care group (control) are followed up at least four times by midwives or nurses. Every trip weights are measured. Consultancy is granted for pregnancy complaints, tests, birth and postpartum period but lifestyle advice is not granted. Duration was from 12th week pregnancy till 6 weeks postpartum. It was delivered by nurses and midwives (n = 51)
	Training: Not specified
	Follow‐up:
	Intervention group: In weeks 12–15, the focus was on healthy life and health practices. In weeks 16–18, the focus was on physical activity and exercises. In weeks 20–24, interviews regarding nutrition were held, that is, meal frequency, size, content. On week 37, only weights were followed up and target achievement was reviewed and the intervention was ended. At 6 weeks postpartum obstetric and neonatal outcomes were measured
	Control Group: Women are generally followed up by at least four times by midwives or nurses in standard care. In every follow‐up, weights of women are measured
	Duration: From 12th week of pregnancy to 6 weeks postpartum
Outcomes	Primary outcomes: None
	Secondary outcomes:
	Birth weight
	Birth length
	Timing of outcome assessment: 6 week postartum
Notes	Study start date: June 2011
	Study end date: July 2012
	Time period: 13 months
	Study country: Turkey
	Study limitations:
	Participation in the study was stopped as soon as the sample size determined by the power analysis was obtained without taking case losses into consideration due to the time constraints for the completion of the study. This situation caused the study to be completed with a smaller sample size than planned. Intervention was applied by the same person in the study (first author of this study who was the nurse officially rendering services in the centre on the dates that the study was conducted) within official working hours. From these aspects, the intervention was strong in terms of controlling the contents of consultancy for each participant and “realistic” in terms of applicability by nurses and midwives. However, the fact that the study was conducted in only one centre and the sample group was limited to healthy pregnant women who did not intend to lose weight and had less than two pregnancies even if they were selected randomly is not sufficient for generalizing the results of the study
	BMI pre‐pregnancy:
	Intervention: 23.86 ± 4.10
	Control: 22.82 ± 3.93
	Funding Source: Not specified
	Conflict of Interest: None