Children of mothers who put on extra weight during pregnancy tend to be overweight themselves, increasing their risk of heart disease and other health problems later in life, according to a recent study published in Circulation, a journal of the American Heart Association and reported in press materials from the University of Bristol in the United Kingdom.

For the study, researchers analyzed medical records from more than 5,000 children involved in the University of Bristol’s Children of the ’90s project, an ongoing health study that enrolled 14,000 pregnant women in 1991 and 1992 to follow the health and development of both mothers and children.

When compared with children of mothers who had put on the recommended amount of weight during pregnancy, researchers found that by the age of 9, children whose mothers gained more weight than recommended had more than 2 pounds of extra body fat, lower levels of HDL “good” cholesterol and higher blood pressure.

But this doesn’t mean mothers should starve themselves while pregnant.

According to guidelines from the Institute of Medicine, mothers need to gain a certain amount of weight to have healthy children. Underweight moms should gain about 28 to 40 pounds; those of normal weight should gain about 25 to 35 pounds; overweight mothers should gain about 15 to 25 pounds; and obese ones should gain about 11 to 20 pounds.

Beyond that, scientists can’t pinpoint how much weight pregnant moms should gain.

“What the ideal weight gain is in pregnancy is a much-debated question, and at the moment we do not know the answer,” said lead author Debbie Lawlor, a professor of epidemiology at the University of Bristol.

For information about how exercise can help ensure your baby achieves the right birth weight, click here.