Despite some evidence to the contrary, being overweight before pregnancy may not be linked to having kids with a higher risk for behavioural or intellectual problems, a new study finds.
In recent years, a few studies have found that children born to overweight women tend to have more behavioural problems, including attention-deficit hyperactivity disorder (ADHD), than their peers whose mothers were normal-weight before pregnancy.
There is also some evidence linking mothers' excess pounds to mild learning problems in their children.
But in the new study of about 7,500 British and Dutch children, researchers saw no consistent correlation between mothers' pre-pregnancy weight and their children's intellectual development or risk of ADHD and other behavioural problems.
Links from other factors
Instead, any links appeared to be largely explained by other factors; like the fact that heavier mothers tended to have less education and lower incomes than normal-weight moms.
The findings suggest that mothers' extra weight does not directly affect foetal development in a way that harms children's later cognitive skills or behaviour, the researchers said in their report, published online in Paediatrics.
The analysis, by Dr Marie-Jo Brion, of the University of Bristol in the UK, and colleagues, pools data from two studies on child health and development.
One followed a group of UK children born in 1991 or 1992; the other included Dutch children born between 2002 and 2006.
Overall, Dr Brion's team found no clear connection between mothers' self-reported pre-pregnancy weights and their children's performance on tests of language and other skills at either preschool or school age.
At first glance, there appeared to be some links. Children born to overweight women tended to have lower scores on language tests, for example. But once the researchers adjusted for such factors as parents' education and family income, the relationship no longer held.
Nor was there a consistent link between moms' weight and children's behavioural problems, which were rated by mothers and, in the UK study, by teachers.
The bottom line, according to Dr Brion's team, is that the findings do not support a biological effect of mothers' weight itself.
(Reuters Health, December 2010)