The number of women having an abortion or unintended pregnancy is dropping worldwide as the use of contraception increases, a report said today.

Abortions fell from an estimated 45.5 million in 1995 to 41.6 million in 2003, the research showed.

But experts from the Guttmacher Institute - a not-for-profit sexual health organisation based in the US - said too many women are still undergoing unsafe abortions, with 32 countries having laws that make abortion illegal.

Today's report said progress had been made on reducing abortions and unintended pregnancies but it was uneven, with developing countries mostly progressing at different rates.

A total of 40 per cent of the world's women live in countries with "highly restrictive" abortion laws - virtually all of them in the developing world, the study said.

In Africa, 92 per cent of reproductive-age women live under such abortion laws, and in Latin America, 97 per cent do so.

These proportions have not changed markedly over the past decade, said the study, called Abortion Worldwide: A Decade of Uneven.

Nineteen countries have "significantly reduced" restrictions in their abortion laws since 1997, while only three countries have "substantially increased" legal restrictions.

Unsafe abortion causes an estimated 70,000 deaths each year and five million women are treated annually for complications resulting from unsafe abortion.

Another three million women with complications go untreated, the report said.

Dr Sharon Camp, president of the Guttmacher Institute, said: "The gains we've seen are modest in relation to what we can achieve.

"Investing in family planning is essential - far too many women lack access to contraception, putting them at risk.

"Legal restrictions do not stop abortion from happening, they just make the procedure dangerous.

"Too many women are maimed or killed each year because they lack legal abortion access."

However, the report congratulated the global trend toward liberalising abortion laws.

Dr Camp said abortion is safe and legal in almost all developed countries.

"But in much of the developing world, abortion remains highly restricted, and unsafe abortion is common and continues to damage women's health and threaten their survival."

The report said the worldwide unintended pregnancy rate declined from 69 per 1,000 women aged 15 to 44 in 1995 to 55 per 1,000 in 2008.

The proportion of married women using contraception worldwide increased from 54 per cent in 1990 to 63 per cent in 2003, and also among single women.

However, there were stark differences between countries - 71 per cent of married women in Latin American and the Caribbean were using contraceptives in 2003, but only 28 per cent of married African women were doing so.

Dr Camp said: "The evidence is strong and growing that empowering women with the means to decide for themselves when to become pregnant and how many children to have significantly lowers unintended pregnancy rates and thereby reduces the need for abortion.

"Addressing the unmet need for contraception, which remains very high in many parts of the world, is critical in promoting the wellbeing of women and their families."