A day and a night of labor left Laena Velaryon pale and weak, but finally she gave birth to the son Prince Daemon had so long desired—but the babe was twisted and malformed, and died within the hour. Nor did his mother long survive him. Her grueling labor had drained all of Lady Laena’s strength, and grief weakened her still further, making her helpless before the onset of childbed fever. As her condition steadily worsened, despite the best efforts of Driftmark’s young maester, Prince Daemon flew to Dragonstone and brought back Princess Rhaenyra’s own maester, an older and more experienced man renowned for his skills as a healer. Sadly, Maester Gerardys came too late. After three days of delirium, Lady Laena passed from this mortal coil. She was but twenty-seven. During her final hour, it is said, Lady Laena rose from her bed, pushed away the septas praying over her, and made her way from her room, intent on reaching Vhagar that she might fly one last time before she died. Her strength failed her on the tower steps, however, and it was there she collapsed and died. Her husband, Prince Daemon, carried her back to her bed. Afterward, Mushroom tells us, Princess Rhaenyra sat vigil with him over Lady Laena’s corpse, and comforted him in his grief.
Fire and Blood, by George R.R. Martin, pg 378