Jan. 17 (Bloomberg) -- The U.S. abortion rate fell to its lowest level in more than 30 years as the number of doctors who provide the operations continued to decline, a study found.

There were 1.2 million abortions, or 19.4 for every 1,000 women of reproductive age, in 2005, according to research by the Guttmacher Institute in New York, a New York-based non-profit group focused on reproductive health. Those numbers compare with a peak of 1.6 million abortions, or 27.4 per 1,000 women, in 1990, the researchers wrote.

Increased access to birth control and medical care helped reduce the number of abortions, according to the study. In addition, 87 percent of U.S. counties didn't have an abortion provider in 2005, up from 77 percent in 1978. The research, published in the journal Perspectives on Sexual and Reproductive Health, examined abortions in women ages 15 to 44.

``It could be that women are having a harder time accessing abortion services,'' said Rachel Jones, the lead study author and a senior research associate at Guttmacher, in a telephone interview. ``It could also be that more women are accessing family planning services and using contraception.''

Medical abortions, when women swallow pills to terminate a pregnancy instead of having surgery, accounted for 13 percent of all abortions in 2005. New York-based Danco Laboratories' pill, RU-486, sold under the name Mifeprex in the U.S., was used in 90 percent of medical abortions, the study found.

Medical Abortion

The Danco drug is taken within the first eight weeks of pregnancy to induce a medical abortion by blocking release of the hormone progesterone. Women take two doses of the drug 24 to 72 hours apart, and then have a miscarriage as the lack of hormones causes the uterine lining to shed.

About 1,026 facilities provided medical abortions in 2005, 70 percent more than offered the option in 2000, the study found.

``We knew that RU-486 was having an impact on abortion services,'' Jones said. ``Now we have some numbers to back up that assertion.''

The abortion rate was highest in the District of Columbia, where 54.2 of every 1,000 women terminated a pregnancy, the study found. The lowest rate, less than one per 1,000, was in Wyoming.

An Oct. 12 study in the journal Lancet showed abortion numbers declining around the globe. An estimated 42 million abortions were induced worldwide in 2003, compared with 46 million in 1995, with Europe leading the decline as the former Soviet Union states adopted contraceptives, according to the study.

To contact the reporters on this story: Lisa Rapaport in New York at Lrapaport1@bloomberg.net; Tom Randall in New York at trandall6@bloomberg.net.

Last Updated: January 17, 2008 00:08 EST