The finding held true whether or not a woman developed actual “gestational diabetes” during pregnancy, the researchers noted.
Babies might also be affected: Children born to these women were more prone to obesity, the study found.
“For mothers, high blood sugar is an important risk factor for later development of abnormal blood sugar levels, including type 2 diabetes,” said researcher Dr. Boyd Metzger. He’s professor emeritus of medicine at Northwestern University Feinberg School of Medicine in Chicago.
For the study, Metzger and colleagues used data from a national study that followed mothers and their children for 10 to 14 years after birth.
The results from the original study showed that modestly elevated blood sugar increases the rate of complications for the baby before and after birth.
The latest study compared the long-term effects of blood sugar levels in mothers who had gestational diabetes with those who didn’t.
Metzger’s team found that the harms of even modestly elevated blood sugar levels extended for both mother and child for more than a decade.
Among women with elevated blood sugar during pregnancy, nearly 11 percent had type 2 diabetes 10 to 14 years after giving birth, and about 42 percent had pre-diabetes, the findings showed.
Among women who did not have elevated blood sugar during pregnancy, about 2 percent had type 2 diabetes and just over 18 percent were pre-diabetic at follow-up.
In all, nearly 4,700 mothers were tested for type 2 diabetes, pre-diabetes or other problems related to blood sugar.
In addition, the researchers studied more than 4,800 children for overweight and obesity. The investigators found that 19 percent of the children born to mothers with elevated blood sugar levels were obese, compared with 10 percent of the children of mothers who had normal blood sugar levels.