What is the recommended approach to insulin therapy for a pregnant patient with diabetes who is taking steroids?

Insulin Management for Pregnant Patients with Diabetes on Steroids

Pregnant patients with diabetes receiving corticosteroids require immediate and aggressive insulin dose increases of 50-80% for both basal and prandial insulin, with hourly glucose monitoring initiated at the time of steroid administration to prevent severe hyperglycemia that occurs within 6-24 hours.

Immediate Insulin Adjustments at Steroid Administration

When antenatal corticosteroids (typically betamethasone) are administered, insulin requirements increase dramatically and rapidly:

• Increase total daily insulin dose by 50-80% for both basal and prandial components at the time of steroid administration 1
• Women with pre-existing type 1 or type 2 diabetes require insulin adjustments within 6 hours of steroid administration 2
• Women with gestational diabetes require adjustments within 12-24 hours 2
• Even women with normal glucose tolerance develop significant hyperglycemia (≥140 mg/dL) in 72% of cases following steroids 2

Monitoring Protocol During Steroid Therapy

Intensive glucose monitoring is essential to prevent severe hyperglycemia:

• Check glucose levels hourly from the onset of steroid administration 1
• Continue hourly monitoring for at least 48-72 hours after each steroid dose 1, 2
• Use capillary blood glucose measurements rather than CGM alone when adjusting insulin doses on variable rate intravenous insulin infusion (VRIII) 1
• Target glucose range of 5.0-8.0 mmol/L (90-144 mg/dL) during steroid therapy to balance hyperglycemia risk against hypoglycemia 1

When to Initiate Intravenous Insulin Infusion

If subcutaneous insulin dose increases are insufficient:

• Start VRIII if glucose exceeds 7.0-8.0 mmol/L (126-144 mg/dL) on two consecutive hourly measurements despite increased subcutaneous insulin 1
• Administer substrate fluid: 0.9% sodium chloride with 5% glucose and 0.15-0.3% potassium chloride at 50 mL/hr alongside VRIII 1
• Continue VRIII until glucose stabilizes, then transition back to subcutaneous insulin with appropriate dose adjustments 1

Specific Insulin Regimen Approach

The preferred insulin strategy during pregnancy with steroids:

• Use basal-bolus regimen with rapid-acting insulin analogs (lispro or aspart) for prandial coverage and long-acting insulin for basal needs 3, 4
• Insulin lispro and insulin aspart are FDA-approved for pregnancy and studied in randomized trials 3, 4
• Multiple daily injections and continuous subcutaneous insulin infusion (pump) are both acceptable, with neither demonstrating superiority 3, 5

Duration of Increased Insulin Requirements

Steroid-induced hyperglycemia persists beyond the immediate treatment period:

• Hyperglycemia continues for at least one week after betamethasone administration in 36% of women with normal glucose tolerance and 49% of women with pre-existing diabetes 2
• Maintain increased insulin doses and frequent monitoring for 7-10 days post-steroid administration 2
• Gradually taper insulin doses only after confirming glucose stability 1

Critical Pitfalls to Avoid

• Do not wait for hyperglycemia to develop before increasing insulin—preemptive dose increases at steroid administration prevent severe hyperglycemia (≥160 mg/dL), which occurs in 43-84% of pregnant women receiving steroids 2
• Do not use oral agents (metformin or glyburide) to manage steroid-induced hyperglycemia, as insulin is the only appropriate therapy during pregnancy 3, 4, 6
• Do not rely solely on CGM values when titrating VRIII—use capillary blood glucose measurements for insulin adjustment decisions 1
• Do not continue pre-steroid insulin doses—the 50-80% increase is necessary regardless of baseline glycemic control 1

Pregnancy-Specific Glucose Targets

Maintain strict targets throughout steroid therapy:

• Fasting glucose <95 mg/dL 3, 4, 7
• 1-hour postprandial <140 mg/dL 3, 4, 7
• 2-hour postprandial <120 mg/dL 3, 4, 7
• A1C <6% if achievable without significant hypoglycemia 3

Post-Delivery Insulin Management

After delivery, insulin requirements change dramatically:

• Reduce insulin doses by at least 50% immediately after placental delivery, as insulin resistance drops precipitously 3, 1
• Women with type 1 diabetes become extremely insulin-sensitive postpartum and may initially require much less insulin than pre-pregnancy 3