London- The increased use of the internet by women seeking to buy medication to end unwanted pregnancies in countries where abortion is restricted is worrying campaigners in Britain, a report said Friday.

A medical study published in the British Journal of Obstetrics and Gynaecology found that more than one in 10 customers using one of the most well-known websites required a surgical procedure after taking the medication for an abortion at home.

Women in more than 70 countries where legal access to abortion is highly restricted, including Poland and the British province of Northern Ireland, have used the internet site Women on Web to purchase the drugs for 55 pounds (110 dollars) a time, the study said.

Women on Web is available in five languages and offers the drugs mifepristone and misoprostol. It says a combination of the pills causes the non-surgical termination of a pregnancy and can be used up to the ninth week, the report said.

The website says it helps women "gain access to a safe abortion with pills in order to reduce the number of deaths due to unsafe abortions."

But the study showed that 11 per cent of 400 customers went on to need a surgical procedure - either because the drugs had not completed the abortion or because of excessive bleeding.

Of 200 women who answered questions about their experiences, almost 60 per cent said they were just grateful to have been able to have an abortion in this way, and 30 per cent said it had been stressful but they found the experience acceptable.

Women on Web posts the drugs only to countries where abortion is heavily restricted, and to women who declare they are less than nine weeks' pregnant.

Customers must answer 25 questions before they are allowed to purchase the drugs, and women are advised to have a pregnancy test and an ultrasound if possible.

However, anti-abortion campaigners said women often understated the period of gestation in order to obtain the medication.

"This is very worrying indeed. It's like a cynical form of back-street abortion," said Josephine Quintavalle, of anti-abortion campaign group Comment on Reproductive Ethics. (dpa)