Management of Gestational Diabetes Mellitus in Late Pregnancy

Diagnosis and Admission Criteria

The American Diabetes Association recommends admission for immediate evaluation and initiation of insulin therapy in patients with an OGTT value of 230 mg/dL, which represents severe hyperglycemia that far exceeds diagnostic thresholds for gestational diabetes 1, 2
An OGTT value of 230 mg/dL dramatically exceeds all diagnostic thresholds, with diagnostic cutoffs being 92 mg/dL fasting, 180 mg/dL at 1-hour, or 153 mg/dL at 2-hour 1
Severe glycosuria (4+) indicates significant hyperglycemia with renal glucose threshold exceeded 3
Late gestational age (34 weeks) requires immediate intervention to prevent fetal macrosomia and other complications 2, 4

The American College of Obstetricians and Gynecologists recommends obtaining fasting plasma glucose and HbA1c to differentiate GDM from preexisting diabetes (HbA1c ≥6.5% or fasting glucose ≥126 mg/dL suggests preexisting diabetes) 5
Check baseline electrolytes including potassium before starting insulin therapy, as recommended by the American Diabetes Association 6
Perform comprehensive metabolic panel including renal function, as recommended by the American College of Obstetricians and Gynecologists 2
Check for ketonuria, as women with diabetes in pregnancy are at high risk for ketosis even with moderate hyperglycemia 6
Obstetric ultrasound to assess fetal size, amniotic fluid volume, and estimated fetal weight for macrosomia, as recommended by the American Institute of Ultrasound in Medicine 2

The American Diabetes Association recommends establishing strict glucose monitoring with the following targets: fasting glucose <95 mg/dL, 1-hour postprandial <140 mg/dL, and 2-hour postprandial <120 mg/dL 2, 4, 7

The American College of Obstetricians and Gynecologists recommends insulin as the mandatory first-line treatment for patients with severe hyperglycemia, given the severity of hyperglycemia 2, 4, 7
Start insulin immediately, without attempting lifestyle modification alone, as recommended by the American Diabetes Association 2
Typical starting dose is 0.7-1.0 units/kg of pre-pregnancy or current body weight divided as basal-bolus regimen, as recommended by the Endocrine Society 2
Insulin does not cross the placenta to a measurable extent, making it the safest option, as stated by the American College of Obstetricians and Gynecologists 2, 7

The American Diabetes Association recommends self-monitoring of blood glucose 4-7 times daily, with fasting and 1-hour or 2-hour postprandial measurements after each meal 5, 2
Monitor potassium levels every 4-6 hours while on insulin therapy due to intracellular potassium shift, as recommended by the American Heart Association 6
Daily fetal kick counts and consider non-stress testing given severity of hyperglycemia, as recommended by the American College of Obstetricians and Gynecologists 8
Blood pressure monitoring for hypertensive disorders, which are increased in risk with GDM, as recommended by the American Heart Association 8

The Academy of Nutrition and Dietetics recommends consultation with a registered dietitian familiar with GDM management, with a minimum of 175g carbohydrate, 71g protein, and 28g fiber daily 2, 7
Distribute carbohydrates across three meals and 2-3 snacks to minimize postprandial excursions, as recommended by the American Diabetes Association 2
Avoid caloric restriction, as adequate calories are needed for fetal growth at 34 weeks, as stated by the American College of Obstetricians and Gynecologists 2

The American College of Obstetricians and Gynecologists recommends initiating fetal surveillance at 32 weeks with twice-weekly non-stress tests, and weekly ultrasound to monitor fetal growth and amniotic fluid volume 8
Assess for fetal macrosomia, which increases the risk of shoulder dystocia, as recommended by the American Institute of Ultrasound in Medicine 8

The American College of Obstetricians and Gynecologists recommends planning delivery timing based on glycemic control achieved, with delivery at 39 0/7 to 39 6/7 weeks gestation if requiring insulin/medications, and at 39 0/7 to 40 6/7 weeks if glucose controlled with lifestyle alone 8
Consider cesarean delivery if estimated fetal weight >4500g due to shoulder dystocia risk, as recommended by the American College of Obstetricians and Gynecologists 8
Do not deliver before 38 weeks unless obstetric indications exist, as stated by the American College of Obstetricians and Gynecologists 8

The American Diabetes Association recommends not delaying insulin initiation, as this glucose level will not respond to lifestyle modification alone 2, 4
Do not use oral agents as first-line therapy, due to inadequate efficacy and placental transfer concerns, as stated by the American College of Obstetricians and Gynecologists 4, 7
Urine glucose monitoring is not useful for management decisions, as recommended by the American Diabetes Association 8
Do not use HbA1c alone for monitoring during pregnancy, instead use self-monitored blood glucose, as recommended by the American College of Obstetricians and Gynecologists 5
Monitor for hypoglycemia once insulin started, particularly overnight, as recommended by the American Diabetes Association 4

The American College of Obstetricians and Gynecologists recommends that insulin requirements drop dramatically immediately postpartum, roughly 34% lower than pre-pregnancy 9
Perform 75g OGTT at 4-12 weeks postpartum using non-pregnant criteria to assess for persistent diabetes, as recommended by the American Diabetes Association 5, 9
Lifelong screening every 2-3 years, as this patient has a 10-fold increased risk of type 2 diabetes, as stated by the American Diabetes Association 9
Encourage breastfeeding, which may reduce long-term diabetes risk, as recommended by the American Academy of Pediatrics 9