Little research has been conducted into the effects of ecstasy on pregnant women, although the number of British people taking the drug has increased dramatically in the past 10 years.

Abeer Parkes reports: "Researchers followed the progress of 136 women"

There have been some studies suggesting a link between birth defects and amphetamines, but the results have often been contradictory.

In a letter to The Lancet, researchers from the National Teratology Information Centre in Newcastle and the Royal Edinburgh NHS Trust say they studied 136 babies whose mothers took ecstasy while pregnant.

They were put in touch with the mothers after they expressed concerns to their doctors about the possible risk of taking the drug while pregnant.

Abortions

The majority were under 30 years old. Seventy-four said they only took ecstasy, but 62 had used ecstasy and other illegal drugs.

Most said they were exposed only in the first three months of pregnancy, when they may not have known they were pregnant.

Eleven of the women had miscarriages - no higher than average - but 48 opted for abortions, which was more than the norm.

Although the vast majority of the children were normal, 12 had congenital abnormalities, at least four times higher than the national average.

Two had congenital heart disease - around four times the norm.

The researchers say: "Although this small case series has insufficient statistical power to confirm a causal relation with any particular congenital anomaly, we consider that these initial data are important."

Caution

Harry Shapiro of the Institute for the Study of Drug Dependency (ISDD) said research on the effects of drugs on the foetus always had to be treated with caution.

He said: "You never really know the circumstances of the women and you cannot ever really be certain of strict cause and effect."

Mr Shapiro said users may not give all the details about the extent or range of their drug use and some in the Newcastle study had complex drug histories.

"Even so 66 out of 78 babies had no birth defects," he stated.

He believes the reason why there is very little research on illegal drugs and pregnancy is because there is no real profit motive in it for pharmaceutical companies.

"The government funds some research, but not much because its message is essentially that people should not be taking illegal drugs," he said.

But he said the ISDD had received several inquiries from women worried about the potential impact of ecstasy use on their babies.

"The only thing we would say it that if you know you are pregnant the best advice is not to try substances which no-one knows the effects of," said Mr Shapiro.