Media playback is unsupported on your device Media caption The Guttmacher Institute's Gilda Sedgh on the WHO study into abortion

A rising proportion of abortions worldwide are putting women's health at risk, researchers say.

The World Health Organization study suggests global abortion rates are steady, at 28 per 1,000 women a year.

However, the proportion of the total carried out without trained clinical help rose from 44% in 1995 to 49% in 2008.

The Lancet, which carried the report, said the figures were "deeply disturbing".

Unsafe abortion is one of the main contributors to maternal death worldwide, and refers to procedures outside hospitals, clinics and surgeries, or without qualified medical supervision.

Women are more vulnerable to dangerous infection or bleeding in these environments.

However anti-abortion campaigners disputed the claim that unsafe abortion rates had increased.

Maternal mortality

In developing countries, particularly those with more restrictive abortion laws, most abortions are unsafe, with 97% of abortions in Africa described this way.

In comparison, 95% of abortions in Latin America were deemed unsafe, falling to 40% in Asia, 15% in Oceania and 9% in Europe.

Case study: Akech Ayimba in Kenya I went through an unsafe [and illegal] abortion when I was about 20 years old. I was afraid to go and tell my mother that I was pregnant. I was about to tell her when a close family friend said, "You're going to break her heart." He said there was another option. I was very scared because I didn't know anything about abortion but he told me it was going to be OK and safe. He looked for the money, because I didn't have any at that time, and paid a nurse who took me to a gynaecologist in Kisumu. I was four months pregnant. I was not put under any anaesthetic and on the abortion bed it was such a very painful experience - though it took place in a clinic. After that I was given an injection and I slept for a while and then got up and went home. My life went back to normal but every once in a while I would have sudden pains in my stomach - for more than a year. The pains kept coming - and with low self-esteem looking for love and acceptance I got into another relationship and got pregnant again - I was very naive and did not know much about protection. I thought another abortion would be the easier option. I was able to do my college exams - I didn't want my pregnancy to stop my career. But after a few months of relief, I then went through a lot of psychological trauma - and I hated myself and twice attempted suicide. Kenya now permits abortion if a woman is considered at risk - and I counsel women who have had abortions and suffer psychological and physical problems. I am now pro-life. Kenya case study: ‘There was no anaesthetic’

To compile the figures - often a difficult task in countries where abortion is illegal - the researchers at the Guttmacher Foundation used surveys, official statistics and hospital records.

They concluded that while the abortion rate had fallen since 1995, that drop had now levelled off, and overall, the rise in world population meant that there were 2.2 million more abortions in 2008 compared with 2003.

In the developed world, the proportion of pregnancies ending in abortion fell from 36% in 1995 to 26% in 2008.

Countries with restrictive abortion laws did not have a corresponding decrease in abortion rate - in some cases, the reverse was true.

Professor Beverly Winikoff, from Gynuity, a New York organisation which pushes for access to safer abortion, wrote in the Lancet: "Unsafe abortion is one of the five major contributors to maternal mortality, causing one in every seven or eight maternal deaths in 2008.

"Yet, when abortion is provided with proper medical techniques and care, the risk of death is negligible and nearly 14 times lower than that of childbirth.

"The data continue to confirm what we have known for decades - that women who wish to terminate unwanted pregnancies will seek abortion at any cost, even if it is illegal or involves risk to their own lives."

Dr Richard Horton, the Lancet's editor, said: "These latest figures are deeply disturbing. The progress made in the 1990s is now in reverse.

"Condemning, stigmatising and criminalising abortion are cruel and failed strategies."

Kate Hawkins, from the Sexuality and Development Programme at the Institute of Development Studies, said: "Whether it is legal or illegal, women will seek abortions and obtain abortions.

"This study showed that in 2008, 86% of abortions took place in developing countries and that nearly half of all abortions worldwide were unsafe in 2008.

"That women continue to die in significant numbers because of unsafe abortion is a scandal and is an issue that the development sector should take seriously."

The UK Department for International Development part-funded the study, and International Development Secretary Andrew Mitchell MP said it was a "tragedy" that the number of "back-street" abortions was rising.

"Women should be able to decide for themselves whether, when and how many children to have - but for many this is not a reality as they have no access to family planning.

"Over the next four years, British aid will give 10 million women access to modern contraception, which will prevent millions of unintended pregnancies."

But John Smeaton of the Society for the Protection of the Unborn Child (SPUC) said of the research: "The truth is that countries with strict laws against abortion have lower maternal death rates than countries which allow abortion widely.

"Ireland, where abortion is banned, has one of the world's best maternal health records. Legalised abortion does nothing to improve medical care."