Gestational Diabetes – Not Just a Test Question

by Meghana Kashyap, MS1

As first year medical students, we learn the biochemistry of diabetes. For our exam, we learned that the pancreas secretes the hormone insulin in response to elevated levels of glucose in the bloodstream. Responding to the insulin, cells uptake the glucose and begin anabolic processes—such as building fat stores—in order to better utilize the glucose under conditions of starvation or depleted energy.

There are two classifications of diabetes—Type I is an autoimmune disorder that causes defective pancreas insulin production. Type II is a deficient response to insulin signaling due to many factors, including obesity. In both, the decrease in cellular uptake of glucose in response to insulin causes an unhealthy build up of glucose in the bloodstream—a problem called hyperglycemia.

Women who are pregnant tend to mimic the insulin insensitivity that occurs in diabetics, in order for more glucose to travel from their bloodstream to their developing babies. Sometimes this system is accentuated to an extent that the mother is too insensitive to insulin and too much glucose remains in her bloodstream, causing too much glucose transport to the fetus. This is termed gestational diabetes, and sometimes translates to Type II diabetes in the mother post-partum.

Babies of mothers who have gestational diabetes are typically larger than the average 7-8 pounds, due to the extra glucose during their development. After birth, for a few days, they typically become hypoglycemic—meaning they do not have enough glucose in their cells— because they are secreting extra insulin from their pancreas to battle the excess glucose coming in from their mother.

In the summer of 2011, Texas witnessed the birth of the largest baby ever born in the state. The child was 16 pounds, a rather large result of gestational diabetes. Though many complications can occur due to large size at birth, this baby only suffered minor complications and transient hypoglycemia, just as I had learned in class.

Earlier this month, a woman in China gave birth to a 15.5-pound baby, which led me to the immediate thought of gestational diabetes. The boy, however, did not seem to be the product of any diabetic complication. It is fascinating to me that such a small piece of knowledge from the first course we take in medical school already has me thinking in terms of potential clinical diagnoses when I read news stories.