“We hoped that when he died it would be as a martyr in the cause of Allah.” The Messenger of Allah (ﷺ) said: “In that case the martyrs of my nation would be few. Being killed in the cause of Allah is martyrdom; dying of the plague is martyrdom; when a pregnant woman dies in childbirth that is martyrdom; and dying of drowning, or burning, or of pleurisy, is martyrdom.”
Sunan Ibn Majah Book 24, Hadith 51