摘要:Objectives. We monitored trends in pregnancy by intendedness and outcomes of unintended pregnancies nationally and for key subgroups between 2001 and 2008. Methods. Data on pregnancy intentions from the National Survey of Family Growth (NSFG) and a nationally representative survey of abortion patients were combined with counts of births (from the National Center for Health Statistics), counts of abortions (from a census of abortion providers), estimates of miscarriages (from the NSFG), and population denominators from the US Census Bureau to obtain pregnancy rates by intendedness. Results. In 2008, 51% of pregnancies in the United States were unintended, and the unintended pregnancy rate was 54 per 1000 women ages 15 to 44 years. Between 2001 and 2008, intended pregnancies decreased and unintended pregnancies increased, a shift previously unobserved. Large disparities in unintended pregnancy by relationship status, income, and education increased; the percentage of unintended pregnancies ending in abortion decreased; and the rate of unintended pregnancies ending in birth increased, reaching 27 per 1000 women. Conclusions. Reducing unintended pregnancy likely requires addressing fundamental socioeconomic inequities, as well as increasing contraceptive use and the uptake of highly effective methods. The incidence of unintended pregnancy is a key indicator of a population’s reproductive health, and preventing unplanned pregnancies is a priority for most sexually active men and women. In an effort to improve the nation’s health, the US Department of Health and Human Services includes the goal of reducing the incidence of unintended pregnancy in its Healthy People 2020 initiative, 1 toward which it is important to monitor progress. The most recent estimates of the unintended pregnancy rate for the US population as a whole and for many population subgroups were published for 2006. 2 Since then, new data have been released that allowed the calculation of rates for 2008. There are several reasons why newer estimates are valuable. Since the last analysis, more precise population estimates have become available, and the United States experienced an economic recession beginning in 2007 that has affected women’s reported pregnancy intentions, with many women indicating that because of the economy, they would like to delay pregnancy. 3 Moreover, the recession has affected many providers’ ability to offer family planning services and women’s ability to access basic health care. 4 Some changes in behaviors that affect unintended pregnancy have been noted in recent years. For example, use of highly effective long-acting contraceptive methods increased from 2002 to 2009. 5 By contrast, population shifts, that is, changes in the relative sizes of demographic subgroups, can have an impact on the unintended pregnancy rate even if rates or behaviors within subgroups are unchanged. For example, because rates are high among cohabiting women, the growing number and proportion of cohabiting couples 6 could have led to an increase in the national unintended pregnancy rate since it was last estimated. In this article, we focus on the overall rate and disparities among several key subgroups for 2008 and shifts in intended and unintended pregnancy between 2001 and 2008. We did not include 2006 rates because it was difficult to assess real changes within a short (2-year) time frame.