Diabetes in Pregnancy

Classifications

White’s Classification (1980)

Maternal/Fetal Complications of Diabetes in Pregnancy

Increased Fetal Risks

• Macrosomia
• Hypoglycemia and hyperinsulinemia
• Delayed pulmonary maturity, RDS
• Preterm delivery, operative delivery, birth injury
• Miscarriage or fetal demise rate increased with poor glycemic control
• Increased risk of congenital anomalies if preexisting diabetes (cardiac, neural tube defects, cleft palate, etc.)
• Polycythemia and hyperviscosity
• Hypocalcemia and hyperbilirubinemia
• Hypertrophic and congestive cardiomyopathy
• Hydramnios
• Long term risks for children: obesity, T2DM, lower IQ

Increased Maternal Risks

• Preeclampsia
• Large for gestational age
• Cesarean delivery
• Developing T2DM later in life (if GDM)
• DKA

Pregnancy Management

Glycemic Targets (May differ by institution)

• Fasting: ≤ 95
• One-hour postprandial (PP): ≤ 140
• Two-hour PP: ≤ 120

Antenatal Testing

• Consider starting at 32-34 wks for both pre gestational diabetes and A2GDM, poorly controlled diabetes may require earlier intervention
• 1-2x weekly NSTs starting at 32w–> 2x weekly at at 36 wks–>continued until delivery
• Growth US in third trimester every 3-4wks

Delivery

Timing

• Well-controlled: 39 0/7-39 6/7
• Poorly-controlled: 36 0/7-38 6/7

Mode

• ≥4500 recommend counseling patient that Cesarean delivery is preferred

Postpartum

GDM

• 75g GTT (2h) at the 6 week postpartum visit and every 1-3 yrs thereafter to screen for T2DM
• 30% will develop subsequent metabolic syndrome
• 10-fold higher risk of developing T2DM
• 2.5-3 fold higher risk of developing Non-alcoholic fatty liver disease
• 2-fold higher risk of cardiovascular events

Treatment

_{There are a number of diabetes medications that people can be placed on. For the sake of pregnancy we will talk about metformin and insulin in this post, as they are the most common and recommended safe in pregnancy.}

Medications

1. Metformin:
   • Start at 500mg Once Daily –> BID
   • Titrate up to meet glycemic targets up to 2-2.5g total daily (i.e. 1,000mg BID)
2. Insulin: (Most commonly used, not all inclusive)
   • Long acting: Onset 3-4h, “Peakless”
     • Lantus (Glargine)– Lasts 18-20h
     • Levemir (Detemir)– Lasts 14h
   • Short acting: Onset 15min, Peaks at 1h, Lasts for 3-4h
     • Humalog (Lispro)
     • Novolog (Aspart)
   • Intermediates: Onset 2-4h, Peak 6-10h, Lasts 10-16h
     • Humalin (NPH)
     • Novolin (NPH)

_{Long acting insulin is better at reducing adverse neonatal outcomes (hypoglycemia, hyperbilirubinemia, macrosomia) than NPH insulins. (J Matern Fetal Neonatal Med. 2009 Mar;22(3):249-53)}

Insulin Regimens

Diabetic Ketoacidosis in Pregnancy

Diagnosis:

• Elevated glucose ≥250mg/dL
• Positive serum ketones
• Acidosis on ABG (pH<7.3)
• Serum bicarbonate (<15mEq/L)
• Elevated anion gap (>12)

Treatment: Varies by institution but idea is the same (fluid resuscitation + electrolyte repletion + insulin)

1. IV hydration (0.9% NS):
   • Calculate the body water deficit: [0.6 x body weight (kg)] + [1-(140/serum Na)]= 100mL deficit/kg body weight
     • Hour 1: 1L NS
     • Hour 2-4: 0.5-1L NS/hr
     • Hour 5-24: 250mL/hr 0.45% NS until 80% deficit is corrected
     • *When blood glucose reaches 250mg/dL change fluids to D5NS
   • K needs to be maintained at 4-5 mEq/L (add into the NS bag)
     • normal-reduced on admission: infusion up to 15-20mEq/hr
     • elevated on admission: don’t supplement until normal range, then ad 20-30mEq/L
   • Bicarbonate: if pH is <7.1 on admission
     • add one ampule (44mEq) to 1L of 0.45% NS
2. Insulin:
   • Mix 50u regular insulin in 500mL NS (flush IV tubing before admin.)
     • Loading 0.2-0.4u/kg
     • Maintenance: 2-10u/hr
     • Double the infusion rate if glucose does not decrease by 20% in first 2hr
     • Continue until bicarb and anion gap normalize and the ketosis resolves
       • Give 1 dose subcutaneous insulin prior to discontinuing the drip
3. Labs:
   • Admission:
     • ABG on admission will calculate the pH and anion gap for diagnosis
   • Admission & q1-2h
     • CMP for glucose, ketones, electrolytes