Which factor increases the risk for respiratory complications due to pulmonary hemorrhage in infants?

The factor that increases the risk for respiratory complications due to pulmonary hemorrhage in infants is left-to-right ductal shunting. This phenomenon occurs when there is an abnormal flow of blood from the left side of the heart to the right side, typically due to a patent ductus arteriosus (PDA). In this situation, the increased volume of blood returning to the lungs can lead to pulmonary overcirculation, causing elevated pressures in the pulmonary vasculature. This heightened pressure can contribute to the development of pulmonary hemorrhage and exacerbate respiratory distress.

The other factors, while related to respiratory issues, do not specifically increase the risk of pulmonary hemorrhage to the same extent as left-to-right ductal shunting. Oxygenation issues due to lung maturity can complicate respiratory status but do not directly cause pulmonary hemorrhage. Meconium aspiration can indeed lead to respiratory complications, but its primary impact is on the airways rather than directly causing pulmonary hemorrhage. Transient tachypnea primarily results from fluid retention in the lungs and typically resolves quickly, whereas it doesn't inherently increase the risk of pulmonary hemorrhage.