Abortion rates are higher in countries where the procedure is illegal and nearly half of all abortions worldwide are unsafe, with the vast majority in developing countries, a new study concludes.

Experts could not say whether more liberal laws led to fewer procedures, but said good access to birth control in those countries resulted in fewer unwanted pregnancies.

The global abortion rate remained virtually unchanged from 2003 to 2008, at about 28 abortions per 1,000 women aged 15 to 44, a total of about 43.8 million abortions, according to the study. The rate had previously been dropping since 1995.

About 47,000 women died from unsafe abortions in 2008, and another 8.5 million women had serious medical complications. Almost all unsafe abortions were in developing countries, where the number of family planning and contraceptive programmes have stopped increasing.

"An abortion is actually a very simple and safe procedure," said Gilda Sedgh, a senior researcher at the US-based Guttmacher Institute.

"All of these deaths and complications are easily avoidable," said Dr Sedgh, the study's lead author.

Dr Sedgh and colleagues concluded that the proportion of unsafe abortions rose from 44 per cent in 1995 to 49 per cent in 2008, the last year for which statistics were available and studied in the report. Dr Sedgh acknowledged it was difficult to get an accurate number for unsafe abortions in particular and described their estimates as modest.

They used sources including official statistics, national surveys and hospital records. To account for unreported abortions, they made adjustments and relied on information from other kinds of studies, expert assessments and surveys of women.

The research was published yesterday in The Lancet medical journal.

Abortion rates were lowest in Western Europe – at 12 per 1,000 – and highest in Eastern Europe at 43 per 1,000. The rate in North America was 19 per 1,000.