July 31, 2006
Preterm Birth: Causes, Consequences, and Prevention
In 2004, 12.5 percent of births in the United States were preterm; that is, born at less than 37 completed weeks of gestation. This rate has increased steadily in the past decade. There are significant, persistent, and very troubling racial, ethnic, and socioeconomic disparities in the rates of preterm birth. The highest rates are for non-Hispanic African Americans, and the lowest are for Asians or Pacific Islanders. In 2003, the rate for African-American women was 17.8 percent, whereas the rates were 10.5 percent for
Asian and Pacific Islander women and 11.5 percent for white women. The most notable increases from 2001 to 2003 were for white non-Hispanic, American Indian, and Hispanic groups. Infants born preterm are at greater risk than infants born at term for mortality
and a variety of health and developmental problems. Complications include acute respiratory, gastrointestinal, immunologic, central nervous system, hearing, and vision problems, as well as longer-term motor, cognitive, visual, hearing, behavioral, social-
emotional, health, and growth problems. The birth of an infant preterm can also bring considerable emotional and economic costs to families and have implications for public sector services, such as health insurance, educational, and other social support systems.
The greatest risk of mortality and morbidity is for those infants born at the earliest gestational ages. However, those infants born nearer to term represent the greatest number of infants born preterm and also experience more complications than infants born at term. Preterm birth is a complex cluster of problems with a set of verlapping factors of influence. Its causes may include individual-level behavioral and psychosocial factors, neighborhood characteristics, environmental exposures, medical conditions, infertility treatments, biological factors, and genetics. Many of these factors occur in combination, particularly in those who are socioeconomically disadvantaged or who are members of racial and ethnic minority groups.