Gestational Diabetes Management

Indications
Gestational Diabetes

Abnormal Glucose Tolerance Test 3 hour
Preexisting Diabetes Mellitus

Monitoring
Blood Glucose

Frequency of Blood Glucose Monitoring
1. Insulin therapy
  1. Blood Sugar Monitoring 4 times daily
2. Diet control
  1. Blood Sugars 4 times on 2 days per week
  2. Increase monitoring if 2 values/week abnormal
Target Levels
1. Before Breakfast or early morning (2-6 am): 60 to 95 mg/dl
2. Before Lunch,Dinner: 60 to 115 mg/dl
3. One hour post prandial goal: under 140 mg/dl
4. Two hour post prandial goal: under 120 mg/dl
5. Check Urine Ketones in early morning
Preferred monitoring: Postprandial Blood Glucose
1. Post-prandial Blood Glucose Monitoring preferred
2. Associated with improved outcomes
  1. Lower Hemoglobin A1C levels
  2. Lower birth weights
  3. Fewer Cesarean Sections
3. References
  1. De Veciana (1995) N Engl J Med 333:1237-41 [PubMed]

Evaluation
Initial

Diabetic Diet
Diabetic nurse Consultation
Initiate home Blood Sugar Monitoring
1. See Blood Glucose Monitoring above

Management
Diet controlled management

Indications
1. Blood Sugars within target range (see above)
Monitoring
1. See Blood Glucose Monitoring above
Dietary recommendations
1. Restrict carbohydrates to <33 to 40% of daily calories
2. Some studies have recommended a low Glycemic Index diet
3. Caloric restriction if BMI > 30 kg/m2
  1. Limit to 25 KCal/kg of actual weight per day
  2. Weight Gain in Pregnancy >40 pounds (18 kg) is associated with Fetal Macrosomia in 40% of cases
    1. Black (2013) Diabetes Care 36(1): 56-62 [PubMed]
  3. Avoid severe caloric restriction
    1. Ketonemia associated with psychomotor delay
    2. Rizzo (1995) Am J Obstet Gynecol 173:1753-8 [PubMed]
Exercise recommendations
1. Regular aerobic Exercise improves glycemic control
2. Circuit Resistance Training improves glycemic control
  1. Brankston (2004) Am J Obstet 190:188-93 [PubMed]

Management
Oral Hypoglycemics

Indications: Failed diet control (see above)
1. More than 50% of Glucose values in a week are above goal (see above) OR
2. More than 2 Glucose values >10 mg/dl above goal at the same meal in a 2 week period
Precautions
1. Oral agents are first-line Gestational Diabetes agents
  1. Followed experimental use in 2005-2010 to confirm safety, efficacy
2. Metformin is not FDA approved in pregnancy
  1. However, it is pregnancy category B
3. Metformin crosses the placenta
  1. However, it is not associated with birth defects or short term adverse neonatal outcomes
  2. Metformin is the only Oral Hypoglycemic that appears safe in pregnancy
4. Sulfonylureas are not recommended in pregnancy
  1. Of the Sulfonylureas, only Glyburide is a pregnancy category B
  2. Glyburide was initally thought the only safe Sulfonylurea in pregnancy
    1. Jacobson (2005) Am J Obstet Gynecol 193(1): 118-24 [PubMed]
  3. As of 2015, Glyburide is no longer recommended in pregnancy as of 2015
    1. Greater risk of Neonatal Hypoglycemia and macrosomia (compared with Insulin)
    2. Balsells (2015) BMJ 350:h102 [PubMed]
5. Insulin is FDA approved in pregnancy and has a longer track record
  1. Up to 40% of women started on Oral Hypoglycemics require transition to Insulin in pregnancy
Glucophage (Metformin)
1. Start at 500 mg once daily with food and titrate to a maximum of 2500 mg daily
2. Glucophage has also been used in Metabolic Syndrome and PCOS to facilitate conception (effective in 42% of cases)
  1. If patient conceives on Glucophage, continue for first 20 weeks (prevents Rebound Hyperglycemia)
3. Rowan (2008) N Engl J Med 358(19):2003-15 [PubMed]
4. Glueck (2002) Hum Reprod 17:2858-64 [PubMed]
References
1. Greene (2000) N Engl J Med 343:1178-9 [PubMed]
2. Langer (2000) N Engl J Med 343:1134-8 [PubMed]

Management
Insulin

Indications
1. Failed diet control (see above)
  1. Fasting Blood Glucose > 95 mg/dl or
  2. Two hour postprandial Blood Glucose >120 mg/dl
2. Preexisting Insulin Dependent Diabetes Mellitus
Protocol
1. See Insulin Management in Pregnancy
2. See Insulin Management in Labor
3. Endocrine consult as needed for Insulin Dosing

Monitoring
Antepartum aggressive monitoring for complications

Aggressive monitoring is not needed for diet controlled Gestational Diabetes (no medications)
1. No increased risk of Stillbirth
2. Loomis (2006) J Fam Pract 55(3): 238-40 [PubMed]
3. Mitanchez (2010) Diabetes Metab 36(6 pt 2): 617-27 [PubMed]
Monitoring as directed by local established protocols
Monitoring starting at 32 weeks gestation
1. Weekly Non-Stress Test (biweekly if on Insulin or poor control)
2. Amniotic fluid index weekly if on Insulin or poor control
3. Some protocols include Biophysical Profile
Daily Fetal Kick Counts starting at 34 weeks gestation
Obstetric Ultrasound monthly
1. Assess Fetal Growth for macrosomia
2. Not universally adopted as Ultrasound may unnecessarily increase the cesarean delivery rate
  1. Little (2012) Am J Obstet Gynecol 207(4): 309.e1-309.36 +PMID:22902073 [PubMed]
Prenatal Visit frequency and monitoring based on Blood Sugar control
Plan Labor Induction by 39-40 weeks

Management
Intrapartum

See Insulin Management in Labor
Timing of delivery
1. Consider offering Cesarean Section for EFW > 4500 g (9 lb 14 oz)
2. Delivery prior to 40 weeks not indicated unless
  1. Poor glycemic control
  2. Other fetal or maternal complications

Management
Postpartum Care

Consider Glucose Tolerance Test 2 hour (75 g Glucola)
1. Non-Lactating: Schedule at 6-12 weeks
2. Breast Feeding: Schedule at 6 months
3. Abnormal in up to 36% in post-partum women
Prevention
1. Maintain Ideal Body Weight
2. Moderate intensity Exercise for 150 minutes per week
Fasting Blood Glucose every 1-3 years
1. Risk of developing Type II Diabetes Mellitus within 10 years (GDM high risk groups): 50%

References