High Blood Sugar Tied to Pregnancy Complications
Wednesday, May 7, 2008; 12:00 AM
WEDNESDAY, May 7 (HealthDay News) -- Women with high blood sugar levels during pregnancy face an increased risk of complications, even if the high blood sugar readings don't meet the criteria for gestational diabetes.
In a large, international study, researchers found that for each standard deviation increase in blood sugar, there was a greater risk of complications, such as having a large birth weight baby or needing a Caesarean section delivery.
"We found strong independent associations between a mother's blood sugar levels during an oral glucose tolerance test and 28 weeks of gestation and the pregnancy outcomes," said the study's lead author, Dr. Boyd Metzger, the Tom D. Spies professor of metabolism and nutrition at the Feinberg School of Medicine at Northwestern University in Chicago.
What this means for pregnant women right now, however, isn't clear.
"Because the relationship between the mother's blood glucose level and risk tend to be continuous and linear, it is not clear where the risk reaches the point where treatment should optimally begin," said Metzger.
"We were hoping there would be a breakpoint," explained another of the study's authors, Dr. Don Coustan, professor and chair of obstetrics and gynecology at the Warren Alpert Medical School of Brown University in Providence, R.I. "But, the relationship between glucose levels and outcomes were continuous, which means it will be difficult to decide where to put the 'treating' point."
Coustan added that there will be a conference in June where pregnancy and diabetes experts will likely debate the pros and cons of treating hyperglycemia. For now, he said, he suspects that "doctors will still use the glucose threshold they're currently using."
One thing that was clear from the study is that higher odds of complications, like an increased risk of C-section or a large baby, are related to high blood sugar and not to other conditions, such as obesity or older maternal age, according to Metzger.
Results of the study were published in the May 8 issue of theNew England Journal of Medicine.
The study included more than 23,000 pregnant women from 15 centers in nine countries. None of the women had diabetes. All of the women underwent glucose tolerance testing between 24 and 32 weeks of gestation. This test is performed by first taking a fasting blood sugar reading, then having the woman drink a high-carbohydrate liquid -- in this case a 75-gram carbohydrate drink; 100 grams is standard in the United States -- and then rechecking blood sugar levels at one and two hours to assess how the body is processing the high sugar load.
The higher a woman's blood sugar levels were, the more likely she was to have a C-section, to develop preeclampsia, have premature delivery and to have the delivery complication known as shoulder dystocia, the study found.
Babies born to women with higher glucose levels were more likely to have high insulin levels, low blood sugar, and to have a large birth weight, all indications of exposure to high glucose levels.