Which statement best describes how fetal glucose exposure changes as maternal glucose rises?

• A. Fetal glucose exposure is saturated
• B. Fetal exposure decreases
• C. Fetal uptake becomes excessive as maternal glucose increases
• D. Fetal exposure unaffected

Answer: (C)

Glucose crosses the placenta by facilitated diffusion, so fetal glucose exposure tracks maternal levels rather than saturating or remaining the same. As maternal glucose rises, fetal glucose in the circulation also rises, and the fetal pancreas responds with increased insulin. That insulin promotes more glucose uptake by fetal tissues, so fetal uptake becomes excessive as maternal glucose increases. This can drive fetal growth (macrosomia) and, after birth, contribute to neonatal hypoglycemia when maternal glucose supply is suddenly removed.