A nationally representative study of maternal obesity in England, UK: trends in incidence and demographic inequalities in 619 323 births, 1989–2007

Background: There is an absence of national statistics for maternal obesity in the UK. This study is the first to describe a nationally representative maternal obesity research data set in England. Design: Retrospective epidemiological study of first trimester obesity. Methods: Data from 34 maternity units were analysed, including 619 323 births between 1989 and 2007. Data analysis included trends in first trimester maternal body bass index status over time, and geographical distribution of maternal obesity. Population demographics including maternal age, parity, ethnic group, deprivation and employment were analysed to identify any maternal obesity-associated health inequalities. All demographics were tested for multicollinearity. Logistic regression analyses were adjusted for all demographics as confounders. Results: First trimester maternal obesity is significantly increasing over time, having more than doubled from 7.6% to 15.6% over 19 years ( P