Women who drink moderate to heavy amounts of alcohol during the early stages of pregnancy may damage their placenta, a new study has found.

The placenta is an organ attached to the wall of the uterus and the umbilical cord of a growing baby. It is responsible for supplying everything that the baby needs, including oxygen and nutrients. It also removes waste products from the baby's blood.

UK researchers decided to investigate the effect of alcohol on the placenta in the first few weeks of development - a period that is essential for normal development.

They studied placentas in a laboratory and found that cell growth in these organs was reduced if women consumed moderate or high amounts of alcohol. This meant that the normal growth and function of the placenta could be adversely affected.

Moderate consumption was considered two-to three standard drinks, while high consumption was considered four to six drinks.

Low levels of alcohol - a half or one standard drink - did not appear to affect cell growth.

The researchers also found that moderate or high consumption of alcohol appeared to reduce the transport of an important amino acid - taurine - from the mother to her baby via the placenta.

This amino acid is essential for brain and physiological development. Reduced levels have been linked to poorer behaviour and physical development. The researchers suggested this may be why the children of alcoholic mothers sometimes display neurological symptoms.

"Alcohol and acetaldehyde (its major toxic breakdown product) are known to be toxic at high levels, but these results clearly show that levels easily achieved in a normal population have specific effects in the placenta.

"Placental growth is reduced in comparison to non-exposed placentas, suggesting that in the long-term, there could be consequences to how much support the infant receives from the placenta during the rest of the pregnancy after this exposure," the researchers from the University of Manchester said.

They noted that the safest clinical advice a woman can be given is to simply abstain from alcohol while pregnant.

"This research also suggests that women who are trying to conceive should not drink as the damage caused by alcohol can happen very early on in pregnancy - perhaps before a woman knows she is pregnant," they added.

Details of these findings are published in the journal, PLoS One.

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