Pregnant women with elevated blood sugar have a greater risk of giving birth to babies with health risks similar to those born to women with gestational diabetes.
These risks include a greater likelihood of the baby being delivered by Caesarean section, the baby being large at birth and the baby's shoulder becoming stuck in the mother, which halts delivery.
This risk assessment applies to pregnant women who have higher than normal blood sugar levels, but who are not considered to have diabetes, versus women with normal blood sugar levels.
The researchers could not identify a specific blood-sugar level above which the health problems were likely to occur. However, they did notice that the risks increased in relation to a rise in the women's blood sugar levels.
They found that, the higher the mother's blood sugar levels:
- the greater chance of a Caesarean-section delivery,
- the more likely the babies were to have high insulin levels and low blood sugar at birth,
- the more likely the mother was to develop preeclampsia (a potentially lethal complication related to very high blood pressure),
- the more likely the baby was to be born prematurely,
- the more likely the baby was to experience shoulder dystocia.
When the researchers included other factors that might lead to these complications, such as higher maternal age, obesity and high blood pressure, high blood sugar levels still accounted for the increased risks.
The new study was funded by the United States National Institutes of Health (NIH), and included 23,000 women. The findings are published in the New England Journal of Medicine.
"These important new findings highlight the risks of elevated blood sugar levels during pregnancy," Dr. Duane Alexander, director of the National Institutes of Health's Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a statement.
"NIH-supported studies now in progress will provide guidance on how to manage them. Until the results of those studies are available, all pregnant women should consult a health-care professional about being screened for diabetes during pregnancy."
It is well known that gestational diabetes, which occurs in some women when they have difficulty transferring sugar from the blood to the body's tissues, increases health risks for both mothers and babies. Their children may also face greater health problems in adulthood, such as obesity, diabetes, high blood pressure and heart disease.
