A new government study claims diabetic women who get pregnant are three to four times more likely to have a child with birth defects than other women.

It found nearly 40 types of birth defects are significantly more common in the infants of diabetic mothers than in those who weren't diabetic, or who were diagnosed with diabetes after they became pregnant. That's more than was first thought.

The study was led by researchers at the Centers for Disease Control and Prevention and is the largest of its kind. It provides the most detailed information to date on types of birth defects found in the infants of diabetic mothers, including heart defects, missing kidneys and spine deformities.

Birth defects affect one in 33 babies born in the United States, and cause about one in five infant deaths.