In Washington and across the nation, obesity is epidemic. Obesity is a risk to the health of pregnant women and their babies. In 2003, the Washington State birth certificate began collecting the mother’s height which, along with her pre-pregnancy weight, makes calculation of the BMI (Body Mass Index) possible. This fact sheet will describe the prevalence of pre-pregnancy overweight or obesity, as defined by BMI, among Washington women who gave birth from 2003 to 2008, and compare rates for higher-income and lower-income women and by race/ethnicity.