Objective: Pre-pregnancy obesity poses risks to both pregnant women and their infants. This study used a large population-based data source to examine trends, from 1993 through 2003, in the prevalence of pre-pregnancy obesity among women who delivered live infants.
Research methods and procedures: Data from the Pregnancy Risk Assessment Monitoring System in nine states were analyzed for trends in pre-pregnancy obesity (BMI>29.0 kg/m2) overall and by maternal demographic and behavioral characteristics. Pre-pregnancy BMI was calculated from self-reported weight and height on questionnaires administered after delivery, and demographic characteristics were taken from linked birth certificates. The sample of 66,221 births was weighted to adjust for survey design, non-coverage, and non-response, and it is representative of all women delivering a live birth in each particular state. The sampled births represented 18.5% of all births in the United States.
Results: Pre-pregnancy obesity increased 69.3% during the study period, from 13.0% in 1993 to 1994 to 22.0% in 2002 to 2003. The percentage increase ranged from 45% to 105% for individual states. Subgroups of women with the highest prevalence of obesity in 2002 to 2003 were those who were 20 to 29 years of age, black, had three or more children, had a high school education, enrolled in Women, Infants, and Children, or were non-smokers. However, all subgroups of women examined experienced at least a 43% increase in pre-pregnancy obesity over this time period.
Discussion: The prevalence of pre-pregnancy obesity is increasing among women in these nine states, and this trend has important implications for all stages of reproductive health care.