Bigger babies are brainier at birth -- study
(7)
Updated: 2001-08-10 11:12

While it has been established already that IQ at school is linked to birth weight among light babies, new research shows there is a correlation between intelligence and size among children of normal birth weight.

"The focus has tended to be on lightweight babies," said Thomas Matte, senior epidemiologist at the New York Academy of Medicine and co-author of the study published in the British Medical Journal.

"This research suggests the need to look at birth weight across the whole range of babies," he told Reuters.

Researchers at the Academy and at Columbia University examined the relation between birth weight and measured intelligence at age seven years in nearly 3,500 children.

Most fell within the normal weight range, defined as exceeding 2,500 grammes.

They found that there was a direct correlation between weight at birth and Intelligence Quotient (IQ) at age seven, even after factors such as mother's age, race, education and socio-economic status were taken into account.

The association was stronger in boys than in girls. The scientists found that a 1,000-gramme increase in birth weight related to a 4.6-point increase in IQ among boys but only 2.8-point increase among girls.

Matte said that he was puzzled by the difference between the sexes. When siblings were compared, removing factors which could affect IQ such as education and social environment, the link between weight and intelligence in girls was weak.

"In girl siblings the relationship is not statistically significant," he said. "There is a difference in the brain development of boys and girls, and so boys may be more sensitive to factors restricting fetal growth."

"Boys are also larger at birth and grow more rapidly, so if something is restraining fetal growth this may also make them more sensitive."

Matte said research into the link between birth weight and intelligence was too sketchy to be useful for any practical or clinical application, but with time may prove valuable.

"There are programmes aimed at reducing the risk of low birth weight now and these need to continue," he said.

Women who smoked during pregnancy, for example, tended to have lightweight babies because they were born early.

Close

Anita Mui biopic begins shooting Ziyi poses for Playboy Madonna says daughter asked if she was gay

Today's Top News     Top Life News
Australia, US, Japan praise China for Asia engagement         Banker: China doing its best on flexible yuan         Hopes high for oil pipeline deal         Possibilities of bird flu outbreaks reduced         Milosevic buried after emotional farewell         China considers trade contracts in India	Pitt-Jolie wedding so far just rumors       Hunan praises Russian quitted stunt flying       1/17 of Beijing students applies for village jobs       Stolen Van Gogh returned after 7 years       Two women die after using abortion pill       Which do you prefer? TV or sex?