Surgeons saved the life of the 23-year-old womans unborn child after the air strike hit a house in the central Gaza town of Deir al-Balah, emergency services spokesman Ashraf al-Qudra said.
Another air raid killed a senior spokesman for Islamic Jihad, the second largest militant group in Gaza after Hamas, which dominates the territory.
Salah Hasaneins sons, 12 and 15, were also killed in the strike in the southern city of Rafah, Qudra said.
Islamic Jihad confirmed the deaths.
The strikes took the Palestinian death toll in Gaza since Israel launched its offensive on July 8 to 865.
Rockets and mortar rounds fired into Israel have killed three civilians -- two Israelis and a Thai farm worker -- and fighting in and around Gaza has killed 35 Israeli soldiers.
It is the bloodiest conflict around the blockaded Palestinian territory since 2008-9.
Human rights watchdogs say that some 80 percent of the Palestinian dead have been civilians, many of them women or children.