The prevalence of diabetes in women of reproductive age is approximately 3%-7%. In pregnancy there is an increase in resistance to insulin. Much of this insulin resistance occurs in the third trimester when hormones produced by the placenta increase which increases resistance to insulin. Therefore, early intervention to help decrease the incidence of gestational diabetes is key. Pre pregnancy counselling has been beneficial. Nutrition counselling, diet and exercise all play key roles in decreasing the incidence of gestational diabetes. If a pregnant woman is diagnosed with gestational diabetes, she has a 50% chance of developing type II diabetes over the next 20 years.
Screening for gestational diabetes occurs generally between 24-28 weeks. A one-hour glucose tolerance test is performed. If the glucose value is above a designated lab value (in most cases 140mg/dl), then a second test known as a three hour glucose tolerance test is performed to confirm whether gestational diabetes is present. Generally, there needs to be two elevated values to make that diagnosis.
If gestational diabetes is confirmed, then blood glucose self-monitoring is initiated. Depending on your physician, in general, a fasting glucose and a postprandial (after eating) about 1-2 hours after each meal is also tested. Your physician may also check some lab work including a hemoglobin A1C which determines glucose levels over the previous 3 months. Nutrition counselling is very important at this stage. Although optimal dietary composition for pregnancy is not completely understood, wholesome food choices (including 40-50% from complex high fiber carbohydrates, 15-30% from protein, 20-35% from primarily unsaturated fats) are advised. Complex carbohydrates are recommended because they are digested more slowly and are less likely to produce significant blood glucose changes. Patients are encouraged to keep a log of food intake as well as blood glucose levels.
Dietary control of glucose is preferred, but if glucose levels continue to rise then your physician may recommend starting an oral hypoglycemic medication or even insulin. Various types of short, intermediate and long acting insulins can be used. Your physician will closely monitor your blood glucose levels to determine if changes in insulin requirements are needed.
The importance of close glucose monitoring is to prevent obstetric complications related to gestational diabetes. Macrosomia (large babies), polyhydramnios ( large amount of amniotic fluid), shoulder dystocia ( due to large baby) are only some of the obstetric complications that can occur.
As always consult your physician or provider.
Reference: The American College of Obstetrics and Gynecology. ACOG practice bulletin.
The American Diabetes Association.