What is Gestational Diabetes (GDM) ?
Gestational Diabetes is a condition of glucose intolerance (high blood sugar )in a pregnant woman with no previous history of diabetes.
Detection and Diagnosis of GDM
Risk assessment for GDM should be undertaken at the first prenatal visit. Women with clinical characteristics consistent with a high risk of GDM (marked obesity, personal history of GDM, glycosuria, or a strong family history of diabetes) should undergo glucose testing (see below) as soon as feasible. If they are found not to have GDM at that initial screening, they should be retested between 24 and 28 weeks of gestation. Women of average risk should have testing undertaken at 24–28 weeks of gestation. Low-risk status requires no glucose testing, but this category is limited to those women meeting all of the following characteristics:
Age <25 years
Weight normal before pregnancy
Member of an ethnic group with a low prevalence of GDM
No known diabetes in first-degree relatives
No history of abnormal glucose tolerance
No history of poor obstetric outcome
Diagnosis is made by performing oral glucose tolerance test (OGTT) using 75 gm glucose. Blood sugar is checked at fasting, 1 hour and 2 hours. Any one abnormal value confirms the diagnosis.
Perform an initial screening by measuring the plasma glucose concentration 1 h after a 50-g oral glucose load (glucose challenge test [GCT] and perform a diagnostic OGTT on that subset of women exceeding the glucose threshold value on the GCT. ( ie >140 mg/dl)
Treatment of GDM
All women with GDM should receive nutritional counseling, by a registered dietitian when possible, consistent with the recommendations by the American Diabetes Association. Restriction of carbohydrates to 35–40% of calories has been shown to decrease maternal glucose levels and improve maternal and fetal outcomes .
Insulin therapy is advised when nutrional therapy fails to reach the following blood sugar targets:
1 hour PP<140
2 hour PP<180
Metformin a glucose lowering medicine can also be used to treat GDM. However, two thirds of patients using metformin will eventually require insulin therapy.
Programs of moderate physical exercise have been shown to lower maternal glucose concentrations in women with GDM.
Do women with GDM need cesarean section?
GDM is not of itself an indication for cesarean delivery or for delivery before 38 completed weeks of gestation. Prolongation of gestation past 38 weeks increases the risk of fetal macrosomia ( baby weighing >4 kgs) without reducing cesarean rates, so that delivery during the 38th week is recommended unless obstetric considerations dictate otherwise.
Breast-feeding, as always, should be encouraged in women with GDM.
What are the complications associated with GDM?
GDM of any severity increases the risk of fetal macrosomia( baby weighing > 4 kgs). New born baby of a GDM patients may suffer from hypoglycemia, jaundice, polycythemia, and hypocalcemia may. GDM is associated with an increased frequency of maternal hypertensive disorders and the need for cesarean delivery. The latter complication may result from fetal growth disorders and/or alterations in obstetric management due to the knowledge that the mother has GDM.
Women with GDM are at increased risk for the development of diabetes, usually type 2, after pregnancy. Offspring of women with GDM are at increased risk of obesity, glucose intolerance, and diabetes in late adolescence and young adulthood.