Treatment of Gestational Diabetes with Subcutaneous Insulin

Introduction to Gestational Diabetes Management

The American College of Obstetricians and Gynecologists recommends insulin as the preferred first-line pharmacologic therapy for gestational diabetes when medical nutrition therapy fails to achieve glycemic targets, and should be initiated using an individualized basal-bolus regimen with human insulin or rapid-acting analogues combined with NPH or long-acting analogues 1

Insulin therapy should be initiated when fasting glucose is elevated, indicating inadequate glycemic control despite medical nutrition therapy, with a threshold of fasting glucose ≥95 mg/dL 4
The American Diabetes Association suggests that insulin therapy should be considered when 1-hour postprandial glucose ≥140 mg/dL or 2-hour postprandial glucose ≥120 mg/dL, indicating poor postprandial glucose control 4

No specific insulin regimen has demonstrated superiority in gestational diabetes management, so the approach should target achieving glycemic goals rather than following a rigid protocol, according to the American Diabetes Association 5
A practical starting approach includes distributing insulin as 40% basal and 60% prandial to address the predominantly postprandial hyperglycemia characteristic of gestational diabetes, with adjustments based on glucose patterns from self-monitoring 4

Self-monitoring of blood glucose 4-6 times daily, including fasting and 1-2 hours postprandial, is essential to assess response and guide therapy, as recommended by the American Diabetes Association 5
Monitoring for ketosis, especially with unexplained hyperglycemia or symptoms, is crucial as pregnancy is a ketogenic state and diabetic ketoacidosis can occur at lower glucose levels than in non-pregnant patients, according to the American College of Obstetricians and Gynecologists 2

For women with gestational diabetes requiring insulin, switching to intravenous insulin infusion during labor or cesarean section, and continuing until return to the post-anesthesia care unit, is recommended by the American College of Obstetricians and Gynecologists 7

Stopping insulin immediately after delivery in women with gestational diabetes, and continuing monitoring of blood glucose before and 2 hours after meals for 48 hours, is recommended by the American College of Obstetricians and Gynecologists 7

While insulin is preferred, oral agents such as metformin and glyburide are acceptable alternatives for women unable or unwilling to use insulin, though this recommendation is somewhat controversial, according to the American College of Obstetricians and Gynecologists 1
The American College of Obstetricians and Gynecologists, SMFM, and NICE guidelines support oral agents as reasonable first-line options, but the key consideration is that oral agents cross the placenta and long-term metabolic effects on offspring are unknown 1