A 32-year-old woman presents with fatigue, pallor, and a his…

A 32-year-old woman presents with fatigue, pallor, and a history of heavy menstrual periods. Her laboratory results show a low hemoglobin level, low serum iron, low ferritin, and increased total iron-binding capacity (TIBC). Based on these findings, which of the following is the most likely pathophysiological cause of her condition?