Read Missy's first post, What is Gestational Diabetes?
Gestational diabetes usually has no symptoms. It is diagnosed by a lab test called an Oral Glucose Tolerance Test. In the United States, a screening glucose tolerance test is performed between the 24th and 28th week of pregnancy. This initial screening test usually involves having the pregnant woman consume a pre-mixed drink with 50 grams of glucose, or sugar, and then testing her blood sugar one hour later. If her blood sugar is above a certain level, a second test is done on a different day. The second test involves drinking 100 grams of glucose and having blood sugar tests done at one, two, and three hours later.
The American College of Obstetricians and Gynecologists (ACOG) recommends universal screening, which means that all pregnant women be screened for gestational diabetes. The American Diabetes Association (ADA) used to recommend that women be screened only if they were high-risk, but now the ADA recommends a screening test between 24 and 28 weeks of pregnancy. Recommendations for screening vary for different countries; Canadian physicians, for instance, do not practice universal screening. Also, the type of test used varies throughout the world. For example, some countries use a 50 gram test for diagnosis and some use either a 75 gram test or the bigger dose of sugar in the 100 gram test.
With all the variation and disagreement, how do you know if you are at risk for gestational diabetes? Women are more likely to be diagnosed with gestational diabetes (1) if they belong to certain racial or ethnic groups (Asian, Hispanic, Native American, and African American); (2) if they are overweight or obese; (3) if they have had gestational diabetes in a previous pregnancy; and (4) if they have a family history of Type 2 diabetes.
Although gestational diabetes does not actually fit the criteria for a disease, it does signal the possibility of future health problems for both the mother and the child. The most recent study of gestational diabetes, the HAPO Study (Hyperglycemia and Adverse Pregnancy Outcomes), found that there was a direct link between rising blood sugar and health problems for the pregnant mother and child. The higher the blood sugar rose, the more problems that occurred. Imagine a line on a graph going up in a straight line from left to right. The upshot is that scientists know that lower blood sugars are healthy. The down-fall is that since they found no curve, or a place where the slope of the line increased dramatically, a cut-off for the mark between normal and unhealthy is very hard to determine.
Because there is no very clear cut-off line for diagnosing gestational diabetes, identification and treatment of rising blood sugars is important for the pregnant woman. Clinical centers that focus on diabetes and pregnancy usually have specific guidelines for treating gestational diabetes. For example, the Joslin Diabetes Center recommends that women monitor their blood sugars with a small, easy-to-use meter at home and then work with their health care team to make adjustments in their diet. Dietary treatment usually begins by limiting simple carbohydrates, like breads and pasta, and evaluating how many calories are eaten at each meal. Adding consistent, daily exercise such as walking can help maintain lower blood sugars throughout a woman's pregnancy. If blood sugars continue to rise, the health care team can make adjustments in diet or, if necessary, add insulin to the treatment plan. The goal of treatment is to keep blood sugars as close to normal as possible. By keeping blood sugars normal, the mother is more likely to maintain a healthy weight and blood pressure and the growing baby is less likely to become very large or to have problems at birth.