Is there a link between maternal age at pregnancy and the risk of childhood obesity?

Maternal Age at Pregnancy and Childhood Obesity

There is a significant association between maternal pre-pregnancy overweight/obesity and increased risk of childhood obesity, with children born to mothers with obesity being twice as likely to develop childhood obesity, independent of maternal age and other factors.

Maternal Weight Status and Childhood Obesity Risk

• Pre-pregnancy maternal overweight and obesity significantly increase the risk of childhood obesity, with offspring born to mothers with obesity being twice as likely to develop childhood obesity, independent of maternal age, race, parity, education, gestational weight gain, child gender, and birth weight 1
• Epigenetic programming that occurs at conception and throughout pregnancy predisposes children born to mothers with obesity to a range of chronic metabolic conditions including type 2 diabetes and heart disease 1
• Maternal pre-pregnancy BMI shows a strong positive correlation with child BMI at various ages, with the strongest correlation observed in 16-year-old boys (adjusted r-square = 0.31) 2

Mechanisms Linking Maternal Weight to Childhood Obesity

• Epigenetic modifications during fetal development create an adverse intrauterine environment that impacts fetal development, leading to negative lifelong health consequences for the child 1
• Maternal overweight and obesity increase the risk of excessive gestational weight gain (GWG), which is independently associated with a higher risk of large-for-gestational-age (LGA) births 1
• Children are three times more likely to develop obesity when maternal gestational weight gain exceeds guidelines, independent of maternal BMI 1
• Alterations in placental function, increased inflammation, and altered mitochondrial function are proposed mechanisms linking maternal obesity to childhood obesity 1

Critical Periods for Intervention

• Preconception is a critical period for intervention, as maternal overweight or obesity originates long before pregnancy and achieving optimal weight for conception may take months or years 1
• Pregnancy is recognized as a critical window to optimize maternal health behaviors and lifestyle to benefit the future health of both mother and child 1
• Early childhood interventions are essential, as 37.6% of adolescents with obesity had already been overweight or obese by 4 years of age 2

Intervention Effectiveness

• Lifestyle interventions during pregnancy in obese women have been shown to reduce measures of adiposity (subscapular skinfold thickness and weight-for-age z-score) at 6 and 12 months of age 3
• However, longer-term follow-up studies (3-5 years) found no significant difference in childhood obesity rates between intervention and control groups (aRR 0.97; 95% CI 0.87,1.08) 4
• A maternal healthy lifestyle score (based on high dietary quality, physical activity, healthy pre-pregnancy BMI, not smoking, and no/moderate alcohol intake) is associated with reduced risk of childhood obesity at ages 5 and 9 5

Risk Factors and Prevention Strategies

• Having two obese parents presents the highest risk for childhood obesity, with an odds ratio of 12.0 compared to having two normal-weight parents 6
• Maternal smoking during pregnancy is linked to greater risk of childhood overweight/obesity (OR: 1.91 at age 5 and OR: 2.14 at age 9) 5
• Prevention strategies should focus on supporting women of childbearing age with weight management from preconception and throughout their life course 7
• Public health interventions regarding aspects of lifestyle linked to maternal obesity should occur much earlier in a woman's life 1

Clinical Implications

• Universal screening for gestational diabetes mellitus (GDM) is recommended between 24-28 weeks of gestation, as GDM increases the risk of childhood obesity 8
• Preconception counseling is recommended for women with risk factors for obesity-related pregnancy complications 8
• Early intervention in the preventive work of childhood obesity should start at the antenatal clinic and continue in child health care centers 2

Common Pitfalls and Caveats

• Community awareness of the importance of a healthy weight and preconception health for pregnancy is low, creating barriers to effective intervention 1
• Excessive focus on maternal factors alone may overlook the importance of paternal factors, as having two obese parents presents the highest risk for childhood obesity 6
• Interventions during pregnancy alone may be insufficient to prevent childhood obesity, suggesting the need for continued interventions throughout early childhood 4