Treating women who develop diabetes during pregnancy greatly reduces the chances that their baby will become obese during childhood, says anew study.

The research found that the higher the mother's blood sugar levels, the greater the child's risk of being obese by age five to seven, even if the mother wasn't diagnosed with diabetes.

Untreated high blood sugar nearly doubled the child's risk of becoming overweight or obese, said the study's lead author, Dr. Teresa Hillier of Kaiser Permanente's Center for Health Research in Portland, Ore.

That higher risk disappeared, however, when women with diabetes followed a special diet, exercised or were given insulin. Their children had about the same risk of becoming obese as those whose mothers had normal blood sugar, the researchers found.

"The important message is that the risk of child obesity related to gestational diabetes is potentially reversible," said Hillier, adding that high blood sugar during pregnancy is contributing to the epidemic of childhood obesity.

The research, funded by the American Diabetes Association, is in the September issue of the group's journal, Diabetes Care.

Diabetes leads to birth complications

Gestational diabetes begins during pregnancy and usually goes away after childbirth. The mother's elevated blood sugar can cause the fetus to grow too large, sometimes requiring delivery by caesarean section and can bring on other health problems for the mother and baby.

In the study, 9,439 patients in Oregon, Washington and Hawaii who gave birth between 1995 and 2000were all screened for diabetes. Their children were weighed between the ages of five and seven.

Of the children whose mothers had normal blood sugar levels, 24 per cent were overweight and 12 per cent were obese. For untreated high blood sugar, 35 per cent of the children were overweight and 20 per cent were obese.

In the treated diabetes group, 28 per cent of the children were overweight and 17 per cent were obese.

The researchers found no statistical difference between the treated and normal level groups after taking into account other contributing factors for childhood obesity— including the mother's age, weight gain during pregnancy, size of the baby and ethnicity.

They calculated that children from the untreated highest levels were 89 per cent more likely to be overweight and 82 per cent more likely to be obese, compared to children whose mothers had normal levels. Even those children who had normal birth weights were at increased risk of obesity, the researchers said.

According to the Canadian Diabetes Association, 3.5 per centof Canadian women will develop the condition during pregnancy.

Risk factors for developing gestational diabetes include:

  • Aprevious diagnosis of the disease.
  • Age over 35 years.
  • Obesity.
  • Ahistory of polycystic ovary syndrome.
  • Hirsutism (excessive body and facial hair).
  • Acanthosis nigricans (a skin disorder characterized by the appearance of darkened patches of skin).
  • Being a member of a population considered to be at high risk for diabetes, including women of aboriginal, Hispanic, South Asian, Asian or African descent.