A 36-year-old pregnant woman with gestational diabetes at 19 weeks’ gestation and BMI 33 kg/m2 is advised on pharmacological treatment. Which is the most appropriate initial pharmacological therapy?

• A. Regular insulin
• B. Isophane insulin
• C. Metformin
• D. Glyburide

Answer: (B)

In gestational diabetes that requires medication, insulin is the preferred option because it provides fetal-safe glucose control and doesn’t have the placental transfer concerns seen with some oral agents. Starting with a basal insulin gives steady, background coverage for fasting and overnight glucose, which is especially useful in pregnancy where insulin resistance is increased by placental hormones and obesity (BMI 33) compounds this. Isophane insulin (NPH) is an intermediate-acting basal insulin, offering a convenient regimen that maintains a more constant insulin level over the day. This makes it a sensible initial pharmacologic choice to achieve stable glycemic control before addressing postprandial spikes. If fasting control is good but post-meal glucose remains high, short-acting insulin can be added at mealtimes. Oral agents like metformin or glyburide exist in some guidelines, but they cross the placenta and carry different neonatal risk profiles, so they are not the default first-line option in many protocols.