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.