Study shows that heavy use of alcohol during pregnancy can alter unborn babies’ brains

A study led by Jerold Chun of the Scripps Research Institute in California shows that the people born to alcoholic mothers are likely at the risk of several problems ranging from poor
brain development to loss of ability of hearing and vision that persists throughout their lives.

The study was done by a team of scientists under Jerold Chun and they believe that heavy use of alcoholic drinks during pregnancy can create many genetic problems including the alteration
of the genetic makeup of unborn babies’ brains, which can cause mental and behavioural problems.

The medical problems caused by heavy drinking during pregnancy are well known and documented but on the other hand, scientists are not so sure about the way alcohol can cause such irreversible
damage to the developing brain.

Jerold Chun and his team of neuroscientists investigated the matter and studied how alcohol affected the brains of mice as the animals grew in the womb. The researchers specifically studied
the chromosomes numbers in the foetuses’ brain cells before and after they were exposed to alcohol.

Around a quarter of neurons in 40 chromosomes carried by most brain cells in healthy mice, show "aneuploidy", which means they have a few more or less than usual. On the other hand, human
brains have a similar mosaic of neurons that have lost or gained a few chromosomes.

Speaking to Guardian about their findings, Chun said, “Down’s syndrome tells us there are some aneuploidies that could profoundly influence brain function. One possibility was that drugs
or alcohol could alter the fabric of the developing brain and that would manifest later on as various disabilities.”

He added, “This represents a new, unrecognised basis for altered neural function, which could contribute to developmental defects seen in animal models and human patients.”

Chun’s team gave between 3mg and 4.5mg of ethanol to pregnant mice during their study for every kilogram of bodyweight, equal to two or three bottles of wine for an average woman. As the
nervous systems of the foetuses started to form, they injected alcohol during two weeks into pregnancy.

The researchers witnessed a swift and dramatic effect of the alcohol, as they examined the foetuses’ brains after one day. A threefold rise in severe aneuploidy could be seen in the foetuses’

The mice that were given high doses of amphetamines, about 10mg per kilogram of body weight, instead of alcohol to see whether drug abuse during pregnancy also had a noticeable effect
on foetuses’ brains, showed a tripling in mild aneuploidy.

This is the first study to show that heavy use of alcoholic drinks and drug abuse in pregnancy can trigger dramatic changes to chromosomes in the developing brain. Further details of the
research work have been presented at the Society for Neuroscience meeting in Washington DC on Sunday.