Why pregnant women should avoid herbal cures

by JAMES CHAPMAN, Daily Mail

Pregnant women or those trying for a baby should not take herbal remedies because of the risk of dangerous side effects, an expert warned yesterday.

Edzard Ernst, Britain's only professor of complementary medicine, spoke out as scientists said one of the most popular herbal supplements on the market - gingko biloba - could contain a toxin known to damage the unborn.

Professor Ernst said it was intolerable that many patients use herbal remedies even though they escape regulation because they are sold as food supplements.

'It's a disaster waiting to happen,' he declared. 'We could see another catastrophe like thalidomide.

The findings of research on gingko biloba - an ancient Chinese plant remedy taken to improve memory and concentration - are published today in the magazine New Scientist and the journal Chemical Research in Toxicology.

The substance, derived from the nuts and leaves of the ginkgo biloba tree, has long been used in Asia as a pick-me-up and is gaining popularity in the West.

But researchers have discovered high levels of the toxin colchicine in one brand and warn the problem could extend to other herbal medicines.

During routine tests of placental blood taken from 24 pregnant

women, Dr Howard Petty and his colleagues at Wayne State University in Detroit were surprised to find colchicine in five of them.

The levels were high enough to have harmful effects and were 'entirely unanticipated'.

Colchicine, found naturally in many plants, is sometimes used to treat gout. But it interferes with cell division and can be fatal at high doses.

At lower levels, experts say, it can pass through the placental barrier during pregnancy and cause 'severe damage' to the foetus. Mothers are also advised to avoid it while breast-feeding since the drug may be passed to a child through their milk.

Dr Petty and his team were baffled by the presence of the toxin in the blood samples until they realised that the women with the chemical in their blood had all been taking herbal supplements.

When the researchers tested a popular herbal supplement containing ginkgo biloba bought at a local pharmacy they found that it contained colchicine.

The researchers only tested one sample of ginkgo biloba, though they refused to say which brand. But Dr Petty warned that the problem could apply to other herbal medicines.

'Such supplements should be avoided by women who are pregnant or trying to conceive,' the researchers say.

Professor Monique Simmonds, a phytochemist at the Royal Botanical Gardens at Kew, suspects, however, that other ingredients in the supplement were responsible for the toxic effects.

'I would expect it to be found in extracts of lily, which are also used for memory, rather than gingko,' she said last night. 'It could be that this particular supplement was a mixture.'

She added: 'As the popularity of these supplements increases, we need to ensure the right plants are being grown and the right concentrations are being used.'

Professor Ernst, who works in Exeter University's department of complementary medicine, said many women turned to herbal products during pregnancy or while trying to conceive because they were nervous about the side effects of standard drugs.

Although there was evidence that some herbal supplements were effective remedies, he was not convinced that the benefits outweighed the risks.

'People think that anything that's green must be safe,' he said. 'This latest research is more evidence showing that it isn't. We have virtually no positive safety data for any of the popular supplements.'

In two recent cases in Britain, women developed kidney failure after taking Chinese herbal remedies to combat eczema.

There is also evidence that herbs can interact with conventional medicines. Ginseng, for instance, has few serious side effects, but when combined with warfarin it can increase the medication's blood-thinning effect.

Last year, women using the contraceptive pill were advised to stop using St John's Wort. Used to treat mild depression, it has been found to interfere with some prescription medicines.

A spokesman for the Royal College of Midwives said: 'It should never be assumed that because a therapy is traditional or natural it must be safe.'

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