The Pope's pregnant receptionist has been found dead in her apartment on the outskirts of the city.
Miriam Wuolou, a 34-year-old of Eritrean origin, was seven-months pregnant when her body was discovered.
She had worked at Pope Francis' home and a priests' guesthouse called Santa Marta for years.
The Italian press reports she worked as a kind of gatekeeper for the Pontiff, as well as for the bishops and cardinals who stay there.
The Pope opted to live at the Santa Marta guesthouse after his appointment in 2013, rejecting the grand papal apartments because he found them too sumptuous and he feared isolation.
Ms Wuolou had a serious kind of diabetes which had led doctors to warn her pregnancy was at risk.
Police are investigating a case of neglect and have interviewed family members, her ex-husband from whom she was separated, and most recent boyfriend, thought to be a policeman in the Vatican, according to Rome-based newspaper il Messaggero.
The first external examination of the corpse showed no signs of violence.
Her brother found the body on Friday after he had not heard from her for several days. The autopsy has been carried out, and DNA tests are to be carried out on the foetus.
Vatican spokesman Father Federico Lombardi said. "Pope Francis had been informed of the death. We are all pained by this news."