Gestational diabetes occurs only during pregnancy. According to the American Diabetes Association, it is estimated that gestational diabetes affects 18% of pregnancies.

We don’t know what causes gestational diabetes, but there are some clues. Hormones from your baby’s placenta help your baby to develop and grow. But these same hormones also block the action of the mother’s insulin in her body. This sometimes creates a problem called insulin resistance. Insulin resistance means the mother’s body is having a hard time using the insulin it has even though it might be enough if she were not pregnant. The result is that a woman may need up to three times more insulin when she is pregnant. As long as the women doesn’t become insulin resistant, her pancreas should be able to control her blood sugar.

But if the woman’s body has difficulty using the insulin, the result is the condition we call gestational diabetes. Without enough insulin or when the insulin can’t be used, glucose is not able to leave the blood and be changed into energy. So the glucose builds up in the woman’s blood to high levels. This is called hyperglycemia.

Gestational diabetes affects the mother later in her pregnancy, after the baby’s body has been formed, but while the baby is still growing. For this reason, gestational diabetes does not cause the kinds of birth defects sometimes seen in babies whose mothers had diabetes before they were pregnant.

However, untreated or poorly controlled gestational diabetes can still harm your baby. When you have gestational diabetes, your pancreas is working overtime to produce more insulin, but the insulin is not effectively lowering your blood glucose levels. The insulin your body makes cannot cross the placenta but the glucose can and it does. This means your baby will have higher than normal blood glucose levels. So your baby’s pancreas will start to make extra insulin in order to get rid of this extra glucose. Since your baby is now getting more energy than it needs to grow and develop, the extra energy will be stored as fat.

This extra fat can lead to a macrosomic baby. This is a medical term made up of two Greek words, makros and sōma (μακρός, long, large + σῶμα, body), and just means “large body.” Babies with macrosomia face health problems of their own, including damage during delivery because they can get stuck on the way out. This is not to say all “large” babies have macrosomia. A larger baby that is naturally, genetically designed to be larger is not the same as an unnaturally large baby, which is what we call a macrosomic baby (or at CCBC we refer to them “sugar babies”). These “sugar babies” have grown bigger than they would have if they had received normal levels of glucose during the pregnancy. Macrosomic or Sugar Babies are the ones at risk.

When a baby’s pancreas has to produce extra insulin while it is in the womb, it may cause the baby to have too low of blood sugar after it is born. This happens because the baby’s pancreas will continue to produce the same amount of insulin it needed in the womb to keep the sugar under control. The problem is that once born, the baby no longer has the need for the extra insulin. So his blood sugar may drop low, sometimes dangerously low. Low blood sugar in a newborn will at the very least make breast feeding difficult, and at the very worst can lead to many more serious complications. These babies are also at higher risk for breathing problems. Babies born with excess insulin become children who are at risk for obesity and adults who are at risk for type 2 diabetes.