Wikipedia has a good definition of diabetes: "Diabetes mellitus, often simply diabetes, is a syndrome characterized by disordered metabolism and inappropriately high blood sugar (hyperglycaemia) resulting from either low levels of the hormone insulin or from abnormal resistance to insulin's effects coupled with inadequate levels of insulin secretion to compensate." In other words, a person with diabetes doesn't have enough insulin to handle the sugars in the diet, and glucose, a type of sugar, builds up in the blood.

So why does diabetes develop during pregnancy? The placenta makes substances that counteract the effects of insulin, so the body needs more insulin during pregnancy than it does when not pregnant. Women who had just enough insulin to meet their needs beforehand can become temporarily diabetic in the third trimester. Gestational diabetes is more common in moms with other factors that predispose to diabetes, such as being overweight or having a family history of diabetes.

Although diabetes sounds dangerous, if the mom is able to keep her blood sugars in the normal range, the risks to her and her baby are low. Some moms with gestational diabetes can do well just by avoiding sugars and simple carbohydrates, and by following a diabetic diet. But others will need medicines, like insulin, in order to keep their blood sugars under control. Exercise also helps control blood glucose levels.

If you are diagnosed with gestational diabetes, you will need to test your blood sugar to be sure it remains normal. Typical goals would be under 100 first thing in the morning, and under 120 after meals, but your doctor will give you guidelines to follow. A consultation with a dietitian is helpful, so you can learn how to eat the right amounts of the right foods. And if your sugars run high, taking medication may become necessary for the health of your baby-to-be. 

Why is it important to maintain normal levels of blood glucose during pregnancy? Elevated blood sugar can make babies grow extra large, leading to difficult deliveries. These supersized babies can have trouble with their blood sugars after birth, and are more likely to be overweight later in life. Also stillbirth is more common with uncontrolled gestational diabetes.

Gestational diabetes can be a scary diagnosis, conjuring up thoughts of having to stick yourself with needles and deliver a huge baby. It does require a lot more work and sacrifice on your part than the average pregnancy. But you can learn to do what you have to do to take the best care of your baby for a few months. With good obstetrical care and attention to your blood sugar, diet and exercise, you can have a normal pregnancy and a healthy baby.