New advice says it's better if mothers-to-be and even those who are trying to conceive do not drink at all.

Women should not drink at all during pregnancy to avoid harming their baby, according to the latest government advice.

Until now, official guidance has been that it was perfectly safe for expectant mothers to drink up to four units - around two large glasses of wine - a week.

But the new advice says it's better if mothers-to-be and even those who are trying to conceive do not drink at all.

Limiting consumption to four units a week will only minimise any risk to the baby - not remove it.

Ministers will also expect the drinks industry to put warnings on bottles and cans about the dangers of drinking while pregnant.

The policy shift was welcomed by charities and doctors who say that even low levels of consumption can harm unborn children.

But others said there was no evidence for the change and were concerned the guidance would cause confusion among pregnant women who had followed the previous advice.

The guidance says: "Pregnant women or women trying to conceive should avoid drinking alcohol.

"If they do choose to drink, to minimise the risk to the baby, they should not drink more than one to two units of alcohol once or twice a week and should not get drunk."

It replaces the old guidance issued in 1999, which said "pregnant women or women trying to conceive should not drink more than one to two units of alcohol once or twice a week and should avoid getting drunk".

Women who are trying for a baby should also abstain from drinking because they will not know for several weeks whether they are pregnant or not.

The UK joins countries such as the U.S., France and New Zealand in advising abstinence.

In an apparent contradiction, the Government insists women who have followed previous guidance have not put their babies at risk.

The Health Department said it did not want to alarm those who had followed the previous guidance.

A spokesman said the department had changed its advice to err on the side of caution and because of fears that women were misinterpreting the previous guidelines and were drinking more than they should.

Deputy chief medical officer Dr Fiona Adshead said: "We have strengthened our advice to help ensure that no one underestimates the risk to the developing foetus of drinking above the recommended safe levels.

"Our advice is simple: Avoid alcohol if pregnant or trying to conceive. This advice could also be included on alcohol packaging or labels."

However, Sarah Hart, editor of Pregnancy and Birth magazine, said it was confusing. "The message is don't drink more than two drinks and, at the same time, women should avoid alcohol," she said.

"It's not been well communicated probably because, although evidence shows heavy drinking is damaging to the foetus, it isn't there for minimal drinking.

"It's a common worry for women, especially if they have been drinking before they knew they were pregnant."

Two thirds of expectant mothers admit to drinking during pregnancy, and one in 20 say they regularly exceed the present limit.

Some scientists claim that even very small amounts of alcohol could result in foetal alcohol syndrome, which causes problems including low birth weight, short stature, flattened features, heart and kidney abnormalities, deafness and brain damage leading to poor hand-to-eye coordination and behavioural difficulties.

It affects one in 1,000 babies and is the leading cause of retardation in the western world.

A milder form of the condition called Foetal Alcohol Spectrum Disorder has also come to light.

It causes attention deficit disorder, hyperactivity and poor coordination. American research has shown that one in 100 unborn babies contract the disorder.

Dr Sheila Shribman, the Government's maternity czar, said: "Although there is still scientific uncertainty about the precise impact of excess alcohol on unborn babies we believe the time is right to introduce a strong consistent approach across the whole of the UK."

The Government is due to announce next week that, following a voluntary agreement with the drinks industry, all bottles and cans should bear the message: "Avoid alcohol if pregnant or trying to conceive".

FOR AND AGAINST: Should pregnant women ever drink at all?

Is it really best for expectant mothers to avoid alcohol altogether? Here two medical experts argue the cases for and against:

YES says Peter Hepper, Professor of Psychology at Queen's University, Belfast

The new Government guidelines on alcohol consumption during pregnancy are to be welcomed in that they raise the profile of a potential cause of harm to the individual which is entirely preventable. But do they go far enough?

Exposure to alcohol during pregnancy may give rise to a constellation of effects, ranging from severe neurological or structural effects to cognitive and behavioural problems. These are problems that persist throughout childhood, adolescence and continue into adulthood.

However, the effects of alcohol begin before conception has occurred, influencing fertility potentially and making it more difficult to conceive.

The advice should also be extended to men because alcohol can affect sperm production and quality.

The key issue is, at what level does alcohol consumption become harmful to the foetus?

Research has indicated that one or two glasses of wine directly affect the behaviour of the foetus.

Thirty minutes after drinking a glass, foetal breathing movements (the foetus is not actually breathing air but may be practising these movements for its time outside of the womb) cease totally.

They remain absent for one to two hours. The greater the amount drunk the longer the time that breathing movements are disrupted.

These effects are most likely caused by some action of alcohol on the nervous system, including the brain of the foetus.

Studies show that drinking two or three glasses of alcohol over a week may disrupt the behavioural repertoire of the foetus.

A foetus spontaneously startles in the womb. Basically it acts as if someone had crept up behind it and shouted 'boo'. This is a product of the developing nervous system.

As the foetus develops, this primitive pattern of behaviour disappears. However, in those exposed to alcohol, these startles disappear at a slower rate, suggesting exposure to alcohol delays the development of the nervous system.

One glass of wine for the foetus is not the same as for an adult. With underdeveloped physiological systems it is unable to break down alcohol as fast as adults.

The evidence suggests some key points: one glass of alcohol changes the foetus's behaviour through an effect on its nervous system; two to three glasses delay the development of its behaviour and nervous system; alcohol persists for longer on the foetus.

The influence of these effects for the long-term development of the individual is unknown and in desperate need of study.

However, there is one conclusion which cannot be challenged - if the mother doesn't drink there can be no effects of exposure to alcohol.

This cannot be said for any other amount of alcohol. Why take the risk?

NO says Andrew Shennan, Professor and obstretician at King's College London

Drinking excessive alcohol in pregnancy can cause problems in the baby.

Drinking more than one unit of alcohol a day has been linked to an increased risk of early miscarriages and problems with the baby's growth and development within the womb.

Binge drinking is particularly associated with behavioural problems.

There is a Foetal Alcohol Syndrome when a baby is born with a typical unusual appearance and abnormal behaviour. This occurs in fewer than one in 1,000 pregnancies.

About 1 per cent of pregnancies are thought to have problems in the baby related to alcohol intake, but these are not so obvious.

However, there is no evidence of harm from low levels of alcohol consumption, up to four units a week.

One must remember that many women who do drink excessively will underreport the amount they drink and it is likely that many pregnancies are affected but unrecognised.

However, alcohol is a substance that has been naturally found in the diet for many millennia (as a consequence of natural fermentation) and our bodies do have an enzyme (alcohol dehydrogenase) to deal with it.

It therefore would not be surprising that small amounts of alcohol can be easily dealt with by the body and are unlikely to cause significant harm, including in pregnancy. Women generally have lower levels of this enzyme.

Although it is correct to warn women regarding the dangers of alcohol in pregnancy, and to ensure they limit their intake, it would seem reasonable not to insist on total abstinence.

Calls to do so may be inappropriate and cause feelings of guilt and embarrassment on the rare occasions such as weddings when a pregnant women may perfectly reasonably choose to have a drink.

Making recommendations that are not based on sound evidence could also undermine women's confidence in the information they are given, which may vary between different health professionals.

There is a danger they will ignore important advice - for example not to smoke at all in pregnancy.

In contrast to alcohol, smoking is more likely to be toxic in any dose, is associated with early birth, low birth weight, babies dying, and lower intelligence in the babies born.

It is highly addictive, and there is clear benefit to the baby in the minority of women who are able to give up.

At present more than one in four women in the UK smoke in pregnancy. This is likely to be a far greater problem to the health of unborn children than that of moderate alcohol intake.

It is important to identify women who have problem drinking during or before any pregnancy so that appropriate help can be instigated.

There remains considerable doubt as to whether infrequent and low levels of alcohol consumption (i.e. less than four units a week) convey any longterm harm, particularly in early pregnancy.

Daily Mail