One in five pregnancies worldwide and one in three pregnancies in Europe ends in abortion, according to a new study published in a special female-focused issue of the Lancet.

The study also found that, on average, 90 percent of women worldwide will have an abortion before the age of 45, based on 2003 data. However, many women will have had multiple abortions and many none at all to come to this average.

Although the statistics may seem startling, worldwide rates of induced abortion actually fell 17 percent from 46 million to 42 million between 1995 and 2003.

Click here to read a summary of the study in the Lancet

Unsafe abortion has not declined worldwide, however, and is concentrated in developing countries, according to a study conducted by Dr. Gilda Sedgh of the Guttmacher Institute in New York, Dr. Iqbal Shah of World Health Organization in Switzerland and colleagues.

The researchers calculated worldwide and regional incidences of safe abortions using reports from national reporting systems, nationally representative surveys and published studies. Figures for unsafe abortion were estimated from hospital data, survey and other published studies.

Of the 41.6 million abortions worldwide, 35 million were in the developing countries, and 6.6 million in developed countries.

The worldwide induced abortion rate fell from 35 per 1,000 women ages 15 to 44 in 1995 to 29 per 1,000 in 2003.

That same year, 48 percent of all abortions worldwide were unsafe (up from 44 percent in 1995), and 97 percent of unsafe abortions were in developing countries. In developed countries, 92 percent of abortions were safe

Globally, there were 31 abortions for every 100 live births in 2003, while in Eastern Europe there were more abortions than live births, 105 abortions for every 100 live births, more than double the level of the next highest world region, Eastern Asia (51 abortions for every 100 livebirths).

Eastern Europe also saw the biggest decrease in abortion rates between 1995 and 2003, down 50 percent. The authors attribute this decline to an increased use of modern contraception methods.

"Although abortion rates and ratios in the countries of the former Soviet Union have fallen substantially in recent years, the rates in Eastern Europe remain higher than any other region," the authors wrote. "This finding suggests the need for continued improvements in and expansion of contraceptive service provision. The widespread preference for small families in this region indicates a high level of need for effective contraception."

In Europe as a whole, nearly a third of pregnancies, 32 percent, end in abortion — higher than any other region due to the relatively high rates in Eastern Europe. The lowest proportion (12 percent) was in Africa, with the world average being one in five (20 percent).

The study found that abortion occurred at approximately the same rates where it is broadly legal as where it is highly restricted by law. Click here to read more on that

The abortion rate per 1,000 women in 2003 was similar for Africa, Asia, Europe and Latin America, between 28 and 35, as complete regions, but lower in North America, 21, and Oceania, 17. However, the lowest abortion rate per 1,000 women worldwide was in Western Europe, 12, and the highest in Eastern Europe, 44.

In the developing world, changes in rates of abortion, and actual numbers of abortions, were dominated by developments in China — which accounts for a fifth of abortions worldwide and saw a 20 percent drop in abortions between 1995 and 2003.

"Unsafe and safe abortions correspond in large part with illegal and legal abortions, respectively," the authors wrote. "The findings presented here indicate that unrestrictive abortion laws do not predict a high level of abortion, and by the same token, highly restrictive abortion laws are not associated with low abortion incidence."

The study's authors said the statistics point to an unmet need for contraception.

"In light of the recent mandates of intergovernmental bodies, the contraceptive and abortion technologies now available, and the estimates presented here, prevention of unsafe abortion is an imperative public health goal," they added.

Beth Fredrick, of the International Women's Health Coalition of New York, wrote, "In all the available data, one fact stands out: safe and legal abortion saves women's lives and protects their health. There is no acceptable reason to allow women to die, fall ill, or become infertile as a result of unsafe abortion when the world community has both the knowledge and the means to prevent these deaths."