Why Babies of Diabetic Women with are 2-5 Times more Likely to Develop Birth Defects And How to Prevent it
The babies of women with diabetes are two to five times more likely to develop birth defects than offspring of women without the disease.
Recent animal study at Joslin Diabetes Center in Boston helps explain why.
The research, appearing in the October issue of the American Journal of Physiology: Endocrinology and Metabolism, suggests that high blood glucose levels early in pregnancy deprive the embryo of oxygen thereby interfering with its development.
“Until recently, it was not understood how diabetic pregnancy could cause birth defects. My laboratory wanted to explore this research because the more we know about the effects of the mother’s diabetes on the embryo, the more tools we have to identify therapies that may prevent birth defects in diabetic pregnancy,” says the study’s lead investigator, Mary R. Loeken, Ph.D., an investigator in Joslin’s Section on Developmental and Stem Cell Biology and Assistant Professor of Medicine at Harvard Medical School.
Women with both type 1 and type 2 diabetes run a high risk of having babies with birth defects, especially of the heart and spinal cord. Because these organs form during the first few weeks of pregnancy, coinciding with the time that a woman may first learn she is pregnant, aggressive control of blood glucose levels just before and after conception is critical. “Women with diabetes should be consulting with their healthcare team to be sure they have good glycemic control before becoming pregnant,” says Dr. Loeken. Maintaining blood glucose control continues to be important throughout the pregnancy, but it is particularly important during the first eight weeks, when an embryo’s organs are forming.
In addition to recommending that women with diabetes have good control of their glucose levels before becoming pregnant, Dr. Loeken recommends that obese women who don’t know if they have diabetes but who are planning to become pregnant be tested for diabetes. There have been several recent reports of increased birth defects in the pregnancies of obese women. “Many obese individuals have type 2 diabetes and do not know it, so it is a good idea to bring glucose levels to within the normal range before becoming pregnant, and to monitor women with pre-diabetes closely during pregnancy to make sure that they don’t develop diabetes,” Dr. Loeken says.
Previous research by Dr. Loeken and others has shown that in pregnant mice, high blood glucose levels boost an embryo’s production of free radicals – products of metabolism that cause oxidative stress, and that oxidative stress leads to birth defects.
These new experiments demonstrated that glucose also caused hypoxic stress in embryos.
These results suggest that the lack of oxygen caused by increased glucose consumption triggers the production of free radicals, which then causes birth defects, Dr. Loeken explains.
The researchers also found that administration of high levels of antioxidants – which keep free radicals from wreaking cellular havoc – prevented the decrease in Pax3 expression and birth defects in embryos of diabetic mice. This lends weight to the theory that lack of oxygen and the accompanying increase in free radical production that occurs in mice with high blood glucose levels are what ultimately increase risk of birth defects.
To summarize the steps to prevention are:
1. Check for diabetes before conception
2. If diabetic, ensure tight gluscose control during the entire period from conception to birth; and why not always?
3. High level anti-oxidants may help reduce the oxidative stress. Please consult your health-care professional for definitive guidance on this.
Source: Joslin Diabetes Center
Filed under Diabetes
October 4th, 2005 at 11:02 pm
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