Study protocol for a 15-year follow-up of a randomized controlled trial on lifestyle intervention in pregnancy: assessing long-term effects on body composition, metabolic traits, and mental health in mothers and offspring.

The original randomized controlled trial enrolled 360 pregnant women with obesity from two university hospitals in Denmark.

• Participants were recruited from Odense and Aarhus University Hospitals.
• Inclusion criterion was a BMI ≥ 30 kg/m2.
• Women were randomized to either lifestyle intervention or standard care.
• The intervention included diet counseling and physical activity from 12 weeks gestation until delivery.

A total of 301 mother-child pairs are eligible for the 15-year follow-up.

• The original trial randomized 360 pregnant women.
• 301 mother-child pairs are eligible for follow-up, representing attrition from the original cohort.
• The offspring will be approximately 15 years old at the time of follow-up assessment.

The primary endpoint of the follow-up study is the effect of lifestyle intervention during pregnancy on offspring body composition measured by DXA scanning.

• DXA (dual-energy X-ray absorptiometry) scans will be performed on both mothers and offspring.
• The clinical examination will be approximately 2 hours in duration.
• Additional assessments include fasting venous blood samples, anthropometric measurements, and questionnaires on diet, physical activity, mental health, and health literacy.
• Continuous glucose monitoring and activity tracking will be conducted for 7–10 days.

The study will investigate the influence of pregnancy lifestyle interventions on dysmetabolic traits and metabolic and inflammatory markers in mothers and offspring 15 years post-pregnancy.

• Fasting venous blood samples will be collected from both mothers and offspring.
• Metabolic and inflammatory markers will be assessed at the 15-year follow-up.
• Both maternal and offspring dysmetabolic traits are included as secondary endpoints.

The study will examine the relationship between maternal mental health during pregnancy and postpartum and long-term obesity risk in both mothers and offspring.

• Questionnaires addressing mental health will be administered to both mothers and offspring.
• Health literacy of both mothers and offspring will also be assessed.
• The association between mental health/health literacy and obesity risk is a stated study aim.

Both high maternal BMI and excessive gestational weight gain are described as significant and independent predictors of future obesity in children and adults.

• Maternal obesity is increasingly linked to adverse health effects across generations.
• Childhood obesity is characterized as one of the most critical public health challenges of the twenty-first century.
• The background rationale motivates the investigation of pregnancy-based lifestyle interventions as a potential clinical strategy.