Sunan an-Nasa'i, Volume 4, Book 25, Hadith 3165 (DarusSalam) ⓘ

It was narrated from 'Uqbah bin 'Amir that the Messenger of Allah said: "There are five things, whoever dies of any of them is a martyr. The one who is killed in the cause of Allah is a martyr; the one who dies of an abdominal complaint in the cause of Allah is a martyr; the one who dies of the plague in the cause of Allah is a martyr; and the woman who dies in childbirth in the cause of Allah is a martyr."

أَخْبَرَنَا يُونُسُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا ابْنُ وَهْبٍ، قَالَ حَدَّثَنِي عَبْدُ الرَّحْمَنِ بْنُ شُرَيْحٍ، عَنْ عَبْدِ اللَّهِ بْنِ ثَعْلَبَةَ الْحَضْرَمِيِّ، أَنَّهُ سَمِعَ ابْنَ حُجَيْرَةَ، يُخْبِرُ عَنْ عُقْبَةَ بْنِ عَامِرٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ خَمْسٌ مَنْ قُبِضَ فِي شَىْءٍ مِنْهُنَّ فَهُوَ شَهِيدٌ الْمَقْتُولُ فِي سَبِيلِ اللَّهِ شَهِيدٌ وَالْغَرِقُ فِي سَبِيلِ اللَّهِ شَهِيدٌ وَالْمَبْطُونُ فِي سَبِيلِ اللَّهِ شَهِيدٌ وَالْمَطْعُونُ فِي سَبِيلِ اللَّهِ شَهِيدٌ وَالنُّفَسَاءُ فِي سَبِيلِ اللَّهِ شَهِيدٌ ‏" ‏ ‏.‏