Gestational Diabetes

1. Epidemiology: Prevalence
   1. Overall: 2-5% of pregnant women in U.S.
   2. High risk groups (see below): 14%
2. Risk Factors
   1. Maternal Age > 30 years
   2. Family History of Diabetes Mellitus
   3. Personal History of Diabetes Mellitus
      1. Previous abnormal lab testing
         1. Glucose Challenge Test (GCT)
         2. Glucose Tolerance Test (GTT)
         3. Glycosuria (Urine Glucose positive)
      2. Symptoms of Diabetes Mellitus
         1. Polyuria (pre-pregnant)
         2. Polydypsia
         3. Blurred vision
   4. Prior Pregnancy Complication
      1. History of infant with Macrosomia
         1. Weight exceeds 4000 grams or 9 pounds
      2. History of infant with congenital anomaly
      3. Prior Stillbirth
      4. Habitual Abortions
      5. Preeclampsia
      6. Polyhydramnios
   5. Obesity
   6. Hypertension
   7. Recurrent Urinary Tract Infection
   8. Recurrent Vaginitis
3. Labs: Screening
   1. Glucose Challenge Test (GCT)
      1. Non-fasting patient drinks 50 grams of Glucose and has Serum Glucose drawn at 1 hour
      2. Abnormal if Serum Glucose exceeds 130 mg/dl
      3. Timing of Test
         1. High Risk (See Risk Factors above)
            1. Perform GCT at initial antepartum visit
            2. Rescreen GCT at 24-28 weeks if initially negative
         2. Low Risk
            1. Perform GCT at 24-28 weeks
   2. Glucose Tolerance Test
      1. Indicated for abnormal Glucose Challenge Test
      2. Fasting patient drinks 100 grams of Glucose and has Serum Glucose drawn fasting, 1,2, 3 hours
      3. Interpretation
         1. See Glucose Tolerance Test
         2. Abnormal if 2 or more readings over respective cut-offs (95, 180,155, and 140 mg/dl)
4. Complications: Fetal
   1. Fetal Macrosomia
      1. Operative delivery risk (Ceserean section)
      2. Birth Trauma risk
      3. Shoulder Dystocia
   2. Hypoglycemia
   3. Hypothermia
   4. Hyperbilirubinemia,
   5. Hypocalcemia
   6. Premature birth
   7. Respiratory distress syndrome
   8. Polycythemia Vera (plethora)
   9. Obesity during childhood
5. Complications: Maternal
   1. Longterm risk of developing Diabetes Mellitus: 50%
      1. Consider Diabetes Screening annually
   2. Hypertension
   3. Preeclampsia
   4. Ceserean Section
6. Prognosis
   1. See Gestational Diabates perinatal mortality
   2. Maternal and fetal outcomes are significantly improved with good Blood Sugar control
      1. Crowther (2005) N Engl J Med 352(24): 2477-86
      2. Metzger (2008) N Engl J Med 358(19): 1991-2002
7. References
   1. (2001) Obstet Gynecol 98:525-38