II. Indications: Gestational Diabetes
- Abnormal Glucose Tolerance Test 3 hour
- Preexisting Diabetes Mellitus
III. Monitoring: Blood Glucose
- Standard Glucose monitor is preferred over Continuous Glucose Monitors
- Continuous Glucose Monitors have limited evidence for Gestational Diabetes in 2022
- Frequency of Blood Glucose Monitoring
- Insulin therapy
- Blood Sugar Monitoring 4 times daily
- Diet control
- If well controlled, obtain Blood Sugars 4 times on 2 days per week OR twice daily
- Increase monitoring to four times daily if 2 values/week abnormal
- Insulin therapy
- Target Levels
- Before Breakfast or early morning (2-6 am): 60 to 95 mg/dl
- Before Lunch,Dinner: 60 to 115 mg/dl
- One hour post prandial goal: under 140 mg/dl
- Two hour post prandial goal: under 120 mg/dl
- Check Urine Ketones in early morning
- Preferred monitoring: Postprandial Blood Glucose
- Post-prandial Blood Glucose Monitoring preferred
- Associated with improved outcomes
- Lower Hemoglobin A1C levels
- Lower birth weights
- Fewer Cesarean Sections
- References
IV. Evaluation: Initial
- Diabetic Diet
- Diabetic nurse Consultation
- Initiate home Blood Sugar Monitoring
- See Blood Glucose Monitoring above
V. Management: Diet controlled management
- Indications
- Blood Sugars within target range (see above)
- Monitoring
- See Blood Glucose Monitoring above
- Dietary recommendations
- Restrict Carbohydrates to <33 to 40% of daily calories
- Some studies have recommended a low Glycemic Index diet
- Caloric restriction if BMI > 30 kg/m2
- Limit to 25 KCal/kg of actual weight per day
- Weight Gain in Pregnancy >40 pounds (18 kg) is associated with Fetal Macrosomia in 40% of cases
- Avoid severe caloric restriction
- Ketonemia associated with psychomotor delay
- Rizzo (1995) Am J Obstet Gynecol 173:1753-8 [PubMed]
-
Exercise recommendations
- Regular aerobic Exercise improves glycemic control
- Circuit Resistance Training improves glycemic control
VI. Management: Oral Hypoglycemics
- Indications: Failed diet control (see above)
- Precautions
- Oral agents are first-line Gestational Diabetes agents
- Followed experimental use in 2005-2010 to confirm safety, efficacy
- Metformin is not FDA approved in pregnancy
- However, it is pregnancy category B
- Metformin crosses the placenta
- However, it is not associated with birth defects or short term adverse neonatal outcomes
- Metformin is the only Oral Hypoglycemic that appears safe in pregnancy
- Sulfonylureas are not recommended in pregnancy
- Of the Sulfonylureas, only Glyburide is a pregnancy category B
- Glyburide was initally thought the only safe Sulfonylurea in pregnancy
- As of 2015, Glyburide is no longer recommended in pregnancy as of 2015
- Greater risk of Neonatal Hypoglycemia and macrosomia (compared with Insulin)
- Balsells (2015) BMJ 350:h102 [PubMed]
- Insulin is FDA approved in pregnancy and has a longer track record
- Up to 40% of women started on Oral Hypoglycemics require transition to Insulin in pregnancy
- Oral agents are first-line Gestational Diabetes agents
-
Glucophage (Metformin)
- Start at 500 mg once daily with food and titrate to a maximum of 2500 mg daily
- Glucophage has also been used in Metabolic Syndrome and PCOS to facilitate conception (effective in 42% of cases)
- If patient conceives on Glucophage, continue for first 20 weeks (prevents Rebound Hyperglycemia)
- Rowan (2008) N Engl J Med 358(19):2003-15 [PubMed]
- Glueck (2002) Hum Reprod 17:2858-64 [PubMed]
- References
VII. Management: Insulin
- Indications
- Failed diet control (see above)
- Fasting Blood Glucose > 95 mg/dl or
- Two hour postprandial Blood Glucose >120 mg/dl
- Preexisting Insulin Dependent Diabetes Mellitus
- Failed diet control (see above)
- Protocol
- See Insulin Management in Pregnancy
- See Insulin Management in Labor
- Endocrine consult as needed for Insulin Dosing
VIII. Monitoring: Antepartum aggressive monitoring for complications
- Aggressive monitoring is not needed for diet controlled Gestational Diabetes (no medications)
- Monitoring as directed by local established protocols
- Monitoring starting at 32 weeks gestation
- Weekly Non-Stress Test (biweekly if on Insulin or poor control)
- Amniotic fluid index weekly if on Insulin or poor control
- Some protocols include Biophysical Profile
- Daily Fetal Kick Counts starting at 34 weeks gestation
-
Obstetric Ultrasound monthly
- Assess Fetal Growth for macrosomia
- Not universally adopted as Ultrasound may unnecessarily increase the cesarean delivery rate
- Prenatal Visit frequency and monitoring based on Blood Sugar control
- Plan Labor Induction by 39-40 weeks
IX. Management: Intrapartum
- See Insulin Management in Labor
- Timing of delivery
- Consider offering Cesarean Section for EFW > 4500 g (9 lb 14 oz)
- Delivery prior to 40 weeks not indicated unless
- Poor glycemic control
- Other fetal or maternal complications
X. Management: Postpartum Care
- Consider Glucose Tolerance Test 2 hour (75 g Glucola)
- Non-Lactating: Schedule at 6-12 weeks
- Breast Feeding: Schedule at 6 months
- Abnormal in up to 36% in post-partum women
- Prevention
- Maintain Ideal Body Weight
- Moderate intensity Exercise for 150 minutes per week
-
Fasting Blood Glucose every 1-3 years
- Risk of developing Type II Diabetes Mellitus within 10 years (GDM high risk groups): 50%
