A 6-month-old female presents for a routine well-baby check. She was born at 28 weeks of gestation with a birth weight of 1300 g. Her neonatal course was complicated by respiratory distress syndrome requiring mechanical ventilation, and she received gentamicin during her NICU stay. The parents are concerned about her delayed response to sounds. You explain that her history places her at risk for a hearing deficit. Which of the following is the most significant risk factor for this child’s hearing deficit?
