Ubada bin Samit reported,

The Messenger of Allah ﷺ visited Abdullah bin Rawaha during his illness, but Abdullah did not move aside on his bed to make room for him.The Prophet ﷺ asked, "Who are the martyrs of my nation?"They replied, "The Muslim killed in battle is a martyr."He said, "Then the martyrs of my nation would indeed be few. The Muslim killed in battle is a martyr, dying of the plague is martyrdom, dying of an abdominal illness is martyrdom, drowning is martyrdom, and a woman who dies with her child still inside her is a martyr."

Azami 8123

Sahih

عن عبادة بن الصامت قال

عاد رسول الله ﷺ عبد الله بن رواحة فما تحوز له عن فراشه فقال: من شهداء أمتي؟ قالوا: قتل المسلم شهادة قال: إن شهداء أمتي إذا لقليل، قتل المسلم شهادة، والطاعون شهادة، والبطن والغرق والمرأة يقتلها ولدها جمعا.

الأعظمي 8123صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Jihad
Chapter
Martyrs and the rulings on martyrdom
Section
Martyrs other than those killed in the cause of Allah
Numbering
Jami al-Kamil 8123 (2nd edition)
Azami 8123