The five people were shot during an Israeli military operation in the city of Nablus on Sunday, according to the Palestinian Red Crescent.
The wife of the 26-year-old man who was killed was about to give birth at a nearby hospital when she was informed, the Palestinian Ministry of Health said.
Witnesses say the military operation took place in a densely populated area, just as schools had closed for the day.
Israel confirms that it opened fire after several "terrorists" threw stones at soldiers.
Human rights organizations report increased violence against Palestinians in the West Bank, where at least 42 people have been killed this year, according to UN figures - several of them by Israeli settlers.
