Children, whose mothers take iron tablets during pregnancy, may develop abnormality in behaviour, says a new study.

Researcher Maria Makrides, a nutritionist from South Australia's Child Health Research Institute and team studied 431 pregnant women. Half of them took a daily 20-milligram iron tablet, the rest a placebo, reports online edition of Australian Broadcasting Corporation.

When parents were surveyed about the behaviour of their children, the women who received iron supplements reported more "abnormal behaviour" than those without supplements. The abnormal behaviour was related to peer conduct, socialisation and hyperactivity, it said.

However, the study shows benefit on women's health. Women taking supplements had better iron stores six months after delivery. At the end of their pregnancies, only 3 percent of the women in the iron group had iron deficiency anaemia compared with 11 percent who didn't get extra iron.
 

Makrides says the abnormal behaviour study has to be interpreted with caution because only a small number that is 10 percent of all the children had that and that was based on the parent's assessment.

She says there's a lack of long-term data on what happens to children after iron supplementation in pregnancy, although some studies in developing countries suggest it improves child development.

"What we found was that there was absolutely no difference in the IQ of the children of the mothers who got iron or placebo during pregnancy," she says.

"We are planning to do a longer term study to find out what happens to these kids when they start school," she says