Excessive weight has become one of the major health problems in the United States as well as in other affluent societies. Because of its medical importance and its multifaceted effects on pregnancy, it is discussed separately in this section. The prevalence of obesity in the United States has increased steadily as economic prosperity has increased. For a number of years, obesity has been termed epidemic. Strictly defined, the word epidemic implies a temporary widespread outbreak of greatly increased frequency and severity. Therefore, and unfortunately, obesity more correctly is endemic - a condition that is habitually present. Its prevalence continues to increase. From 1960 to 1991, the National Health and Nutrition Examination Survey (NHANES) documented an alarming increase among adults over the past decade (Kuczmarski and colleagues, 1994). By 1991, approximately one third of adults in the United States were overweight. That same year, Allison and co-workers (1999) attributed almost 300,000 deaths to obesity. Sadly, the problem is not limited to adults. Ogden and associates (2002) reported that 15 percent of children 6 through 11 years of age were overweight. The prevalence in adolescents is similar.

Public health authorities began to address the problem of obesity in the late 1980s. A stated goal of Healthy People 2000 was to reduce the prevalence of overweight people to 20 percent or less by the end of the 20th century (Public Health Service, 1990). Unfortunately, this goal was not achieved, and in fact, more than 50 percent of the population was overweight at the beginning of 2000.

As evidence accrues, the nature and scope of morbidity due to obesity have become betterelucidated. Diabetes mellitus, heart disease, hypertension, stroke, and osteoarthritis are among the many obesity-related diseases. These obesity-related diseases together result in a decreased life span. Bray (2003) aptly concluded that the worldwide obesity epidemic will be followed by a worldwide diabetes epidemic. Obese women who become pregnant - and their fetuses - are predisposed to a variety of serious pregnancy-related complications. Long-term maternal effects include significant and increased morbidity and mortality. Moreover, recent studies have suggested that the offspring of obese parents may suffer long-term morbidity. Ironically, severely growth-restricted female infants who become obese as adults are at high risk for preeclampsia (Dempsey and colleagues, 2003).