Overweight and obesity represents a significant health issue, with 50% of women entering pregnancy with a body mass index >25kg/m2. Obesity is associated with a well-documented increase in risk of complications during pregnancy and childbirth, for both women and their infants. Increasingly, events that occur during pregnancy are recognised to have a critical impact on an individual’s subsequent health and risk of disease, including obesity. This presentation will focus on in-utero factors associated with risk of subsequent obesity, and consider the available evidence for preventive strategies targeting this early-life period.