Gestational Diabetes: Causes, Diagnosis and Treatment
Special Guest Series by Missy Foy
In its international manual of medical diagnoses, the World Health Organization defines gestational diabetes as "carbohydrate intolerance resulting in hyperglycemia of variable severity with onset or first recognition during pregnancy." What exactly does all that mean? And, more importantly, what does that mean for the expectant mother and her unborn child?
We can start with a break-down of the medical jargon. The term "gestational" simply means during pregnancy. "Carbohydrate intolerance resulting in hyperglycemia" means that when starchy foods are digested they enter the blood stream more quickly than your body can use them. The result is that blood sugar rises too much too fast. So, the complex, technical, medical definition essentially refers to a new and temporary rise in blood sugar for a pregnant woman who has not already been diagnosed with diabetes.
To answer the question about what a diagnosis of gestational diabetes means for you during your pregnancy, a little bit of background on diabetes is necessary. There are actually three main categories of diabetes: Type 1, Type 2, and Impaired Glucose Tolerance. Type 1 diabetes results when a person no longer makes insulin. These people need insulin shots. With Type 2 diabetes, insulin is still being made but the cells do not respond well enough and the blood sugar rises too high. Treatment for Type 2 can vary from a special diet with exercise to different types of medicine, sometimes including insulin. In the broad category of Impaired Glucose Tolerance, often called "pre-diabetes," a person still makes their own insulin and blood sugars are usually normal, but certain challenges like starchy foods will cause a temporary rise in blood sugar. Some researchers believe that this is an early sign of Type 2 diabetes. Gestational diabetes falls into this category.
We all have some sugar in our bloodstream all of the time. Too much sugar, though, can injure some of the cells in our bodies. The higher the level of blood sugar, and the longer it remains elevated, the worse the health problems can become. We know that extremely high blood sugars, or blood sugars that stay elevated for long periods of time, are dangerous. But, doctors and scientists have had a hard time pin-pointing exactly when blood sugar levels cross that line between normal and too high. Like many things in medicine, a threshold number is selected by analyzing results from many individuals of many different backgrounds. The problem is that individual results can vary quite a bit, so an exact number that may be too high for one person or for a particular group of people might actually be okay for another individual or group.
For the pregnant woman, pin-pointing exactly when a blood sugar has risen too high is even more difficult for several reasons. During pregnancy, certain hormones can cause a woman to become less sensitive to her own insulin. The result can be a blood sugar that runs a little higher than before her pregnancy. Or, her unborn baby can use some of the extra blood sugar, making the mother's blood sugar test appear normal and, just as in life, over-feeding in the womb can result in problems.
The most common problem that happens with gestational diabetes is that the baby becomes very large from this over-feeding, a condition called macrosomia. Macrosomia can cause injuries during birth (such as dislocation of the baby's shoulders) and can even cause some breathing and blood sugar problems in the first days of life. Also, these babies are more likely to be overweight as children and to develop Type 2 diabetes as adults. The woman diagnosed with gestational diabetes is also more likely to develop Type 2 diabetes later in life.