Which statement best describes the pathophysiology of gestational diabetes?

• A. Increased insulin sensitivity
• B. Autoimmune beta cell destruction
• C. Decreased insulin production
• D. Significant decreases in insulin sensitivity with advancing gestation

Answer: (D)

During pregnancy, hormones from the placenta raise insulin resistance, and this effect grows as gestation advances. If the pancreatic beta cells cannot increase insulin secretion enough to overcome this resistance, maternal blood glucose rises, leading to gestational diabetes. That progressive drop in insulin sensitivity with advancing gestation is the key mechanism.

The other ideas don’t fit gestational diabetes: simply increased insulin sensitivity would lower glucose; autoimmune destruction of beta cells is characteristic of type 1 diabetes; and while some women have inadequate insulin production, gestational diabetes is best explained by inadequate compensatory increase in insulin despite rising resistance.