Musnad Ahmad 1091:10

Rawh narrated to us, Malik narrated to us, from Abdullah ibn Abdullah ibn Jabir ibn Atik, from Atik ibn al-Harith ibn Atik—who is the maternal grandfather of Abdullah ibn Abdullah—that he informed him that Jabir ibn Atik informed him: That when Abdullah ibn Thabit died, his daughter said: "By Allah, I was hoping you would be a martyr, for you had already prepared your equipment." The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Allah has granted him his reward according to his intention. And what do you consider martyrdom?" They said: "Being killed in the way of Allah." The Messenger of Allah (peace and blessings of Allah be upon him) said: "Martyrdom is seven [types] besides being killed in the way of Allah: The one who dies of the plague is a martyr; the one who drowns is a martyr; the one who dies of pleurisy is a martyr; the one who dies of a stomach ailment is a martyr; the one who dies in a fire is a martyr; the one who dies under rubble is a martyr; and the woman who dies during childbirth is a martyr."