Excess maternal weight gain during pregnancy is associated with overweight/obesity in offspring at age 16 years, but maternal pre-pregnancy obesity has a greater effect
- Endocrinology Unit, Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, Edinburgh UK
- Correspondence to: Dr Rebecca M Reynolds
Endocrinology Unit, Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK;
Implications for practice and research
▶ Children of mothers who are obese prior to pregnancy, and/or gain excessive weight in early pregnancy, carry increased risk for obesity in adolescence.
▶ Obese women of childbearing age should be actively supported to achieve lifestyle modification prior to conception or in early pregnancy.
▶ Research is needed to identify strategies for optimal gestational weight gain (GWG) and lifestyle modification before and during pregnancy.
▶ Studies need to identify women at highest risk of excess GWG plus potential benefits of intense dietary and lifestyle counselling.
In the last two decades, UK rates of obesity in pregnancy have doubled, and currently one in five women are obese at antenatal booking.1 Increasing evidence suggests that early life environment impacts on later health of the developing fetus. Maternal obesity and excessive GWG have long-term adverse outcomes for the offspring, including later life obesity.2
This prospective cohort study examined associations between GWG in the first half of pregnancy and obesity levels in 6637 adolescent children from the 1986 Northern Finland Birth Cohort. GWG was calculated as the difference between measured weight at 20 weeks gestation and self-reported pre-pregnancy weight. The children (3265 boys and 3372 girls) were weighed and measured at 16 years. Data were analysed using multivariable logistic regression with GWG as the exposure and covariates of maternal pre-pregnancy body mass index (BMI), smoking, haemoglobin, parity, education, glucose metabolism and offspring gender.
Children of mothers with the highest quartile of weight gain (>7 kg by 20 weeks gestation) had nearly a 1.5-fold increased risk of being overweight or obese at age 16 years. However, having a mother who was obese (BMI>30 kg/m2) prior to pregnancy was associated with more than a fourfold risk of obesity in adolescence. Other associated factors included maternal smoking, lower education levels and gestational diabetes.
This study adds to the literature demonstrating an influence of early life environment on later life health. Both maternal pre-pregnancy obesity and greater GWG, in the first half of pregnancy, were associated with offspring obesity in adolescence. Whether these effects can be modified by lifestyle factors, such as diet and exercise, is unknown, as these factors were not accounted for in the current study. Moreover, the findings may not be generalisable owing to possible unique characteristics in this Northern Finland cohort, such as diet and genetic influences on metabolism.
Importantly, this was not an obese cohort. Approximately 13% of mothers were overweight and only 3–4% were obese, considerably lower than obesity levels seen today.1 Recent recommendations have emphasised pre-conception counselling and support,3 but achieving a normal weight pre-pregnancy may not be realistic for many women. Modifying GWG may be more achievable, particularly as women are motivated to improve health behaviours during pregnancy. However, many obese women are not aware of the associated health risks of obesity during pregnancy. Moreover, healthcare professionals may avoid giving dietary and lifestyle advice, as it is a sensitive issue. There are few specific nutrient guidelines, and lifestyle interventions shown to improve outcomes remain limited.4
This study focused on GWG in the first half of pregnancy, when weight gain reflects expansion of maternal tissues, but maternal dietary composition also influences fetal growth.5 Whether women who gain weight rapidly in early pregnancy continue to gain weight during later pregnancy is unknown, and many women are not routinely weighed throughout pregnancy. Gestation-specific guidelines for optimal GWG have been recommended by the Institute of Medicine, USA,6 but more studies are needed to identify those most at risk of excess GWG and to determine whether women with rapid GWG require more intense dietary and lifestyle counselling. Recording weight and setting GWG goals have been suggested and algorithms to predict GWG are being developed.7 Such strategies may be one step towards preventing future childhood obesity.