Abortion surveillance - United States, 2011.

Problem/condition: Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States.

Reporting period covered: 2011.

Description of system: Each year, CDC requests abortion data from the central health agencies of 52 reporting areas (the 50 states, the District of Columbia, and New York City). The reporting areas provide this information voluntarily. For 2011, data were received from 49 reporting areas. For trend analysis, abortion data were evaluated from 46 areas that reported data every year during 2002-2011. Census and natality data, respectively, were used to calculate abortion rates (number of abortions per 1,000 women) and ratios (number of abortions per 1,000 live births).

Results: A total of 730,322 abortions were reported to CDC for 2011. Of these abortions, 98.3% were from the 46 reporting areas that provided data every year during 2002-2011. Among these same 46 reporting areas, the abortion rate for 2011 was 13.9 abortions per 1,000 women aged 15-44 years, and the abortion ratio was 219 abortions per 1,000 live births. From 2010 to 2011, the total number and rate of reported abortions decreased 5% and the abortion ratio decreased 4%, and from 2002 to 2011, the total number, rate, and ratio of reported abortions decreased 13%, 14%, and 12%, respectively. In 2011, all three measures reached their lowest level for the entire period of analysis (2002-2011). In 2011 and throughout the period of analysis, women in their 20s accounted for the majority of abortions and had the highest abortion rates, and women in their 30s and older accounted for a much smaller percentage of abortions and had lower abortion rates. In 2011, women aged 20-24 and 25-29 years accounted for 32.9% and 24.9% of all abortions, respectively, and had abortion rates of 24.9 and 19.4 abortions per 1,000 women aged 20-24 and 25-29 years, respectively. In contrast, women aged 30-34, 35-39, and ≥40 years accounted for 15.8%, 8.9%, and 3.6% of all abortions, respectively, and had abortion rates of 12.7, 7.5, and 2.8 abortions per 1,000 women aged 30-34 years, 35-39 years, and ≥40 years, respectively. Throughout the period of analysis, abortion rates decreased among women aged 20-24 and 25-29 years by 21% and 16%, respectively, whereas they increased among women aged ≥40 years by 8%. In 2011, adolescents aged <15 and 15-19 years accounted for 0.4% and 13.5% of all abortions, respectively, and had abortion rates of 0.9 and 10.5 abortions per 1,000 adolescents aged <15 and 15-19 years, respectively. From 2002 to 2011, the percentage of abortions accounted for by adolescents aged 15-19 years decreased 21% and their abortion rate decreased 34%. These decreases were greater than the decreases for women in any older age group. In contrast to the percentage distribution of abortions and abortion rates by age, abortion ratios in 2011 and throughout the entire period of analysis were highest among adolescents and lowest among women aged 30-39 years. Abortion ratios decreased from 2002 to 2011 for women in all age groups except for those aged <15 years, for whom they increased. In 2011, most (64.5%) abortions were performed by ≤8 weeks' gestation, and nearly all (91.4%) were performed by ≤13 weeks' gestation. Few abortions (7.3%) were performed between 14-20 weeks' gestation or at ≥21 weeks' gestation (1.4%). From 2002 to 2011, the percentage of all abortions performed at ≤8 weeks' gestation increased 6%. In 2011, among reporting areas that included medical (nonsurgical) abortion on their reporting form, a total of 71.0% of abortions were performed by curettage at ≤13 weeks' gestation, 19.1% were performed by early medical abortion (a nonsurgical abortion at ≤8 weeks' gestation), and 8.6% were performed by curettage at >13 weeks' gestation; all other methods were uncommon. Among abortions performed at ≤8 weeks' gestation that were eligible for early medical abortion on the basis of gestational age, 28.5% were completed by this method. The percentage of abortions reported as early medical abortions increased 3% from 2010 to 2011. Deaths of women associated with complications from abortions for 2011 are being investigated as part of CDC's Pregnancy Mortality Surveillance System. In 2010, the most recent year for which data were available, 10 women were identified to have died as a result of complications from known legal induced abortions. No reported deaths were associated with known illegal induced abortions.

Interpretation: Among the 46 areas that reported data every year during 2002-2011, large decreases in the total number, rate, and ratio of reported abortions from 2010 to 2011, in combination with decreases that occurred during 2008-2010, resulted in historic lows for all three measures of abortion.

Public health actions: Unintended pregnancy is the major contributor to abortion. Because unintended pregnancies are rare among women who use the most effective methods of contraception, increasing access to and use of these methods can help further reduce the number of abortions performed in the United States. The data in this report can help program planners and policy makers identify groups of women at greatest risk for unintended pregnancy and help guide and evaluate prevention efforts.