Five pregnant women in Italy died over the weeklong stretch between Christmas and New Year's Eve, shocking a nation regarded as having one of the safest medical systems for expectant mothers. The deaths, all of which occurred in the north of the country, have sparked a government investigation into how hospital staffing or policies might have contributed to the spate of deaths.

"We have to understand if the recommended procedures were followed or if there were organizational deficiencies," Health Minister Beatrice Lorenzin said in a statement quoted by Agence France-Presse. Authorities are particularly concerned that holiday staffing changes might have influenced patient care at the hospitals in question.

On New Year's Eve, 30-year-old Giovanna Lazzari died during an emergency Caesarean section procedure in Brescia after her fetus died in the womb. She was eight months pregnant when she was admitted with a fever two days earlier.

Her husband, Roberto Coppini, told local press that Lazzari had complained of receiving scant attention from hospital staff. "In a few hours, I lost a baby and a unique mamma. Someone has to tell me what happened," Coppini was quoted saying by AFP.

Brescia, mamma di due bambini muore all'ottavo mese di gravidanza https://t.co/CtSkDNuS7w pic.twitter.com/oIr5cO4veB — Today (@Today_it) January 2, 2016

Other cases followed similar patterns. Marta Lazzarin, a 35-year-old travel writer, died at seven months pregnant. The baby was lost after her water broke, and she was admitted to the emergency room suffering from abdominal pains and fever. She died of a heart attack, the Guardian reported.

Lazzarin's husband penned a post on the couple's travel blog, wishing "Bye-bye, my love" to his late wife.

Those cases, along with three others, represent a rare occurrence in Italy, which has one of the lowest maternal mortality rates in the world at just four deaths per 100,000 births — less than one-third of the maternal mortality rate of the U.S.

The investigation, launched Monday after a mother died of a heart attack in Turin, was expanded after the subsequent deaths came to national attention. "The priority is identifying any errors and preventing other tragedies," Lorenzin said.