The World Health Organization (WHO) launched a training campaign on Wednesday to help reduce the number of maternal deaths during childbirth in developing countries.

The WHO estimates one woman in a developing country dies while giving birth every minute of the day.

Women in poor countries have a 1-in-16 chance of dying in childbirth, compared with a 1-in-2,800 chance for women in wealthier countries, the United Nations health agency said.

Sub-Saharan Africa and central south Asia have the highest rates of maternal death. Bleeding, infection, obstructed labor and unsafe abortions cause most deaths.

The campaign’s launch coincided with the release of a new manual that aims to teach health providers effective methods to prevent childbirth deaths in even the poorest conditions, and how to gather information to improve statistics on such deaths.

“It is time for all of us to turn technical knowledge into action to save the lives of the women who give life,” said one of the authors, Dr. Luc de Bernis. The WHO estimates maternal deaths are under-reported by as much as 50 percent. Sixty-two countries have no maternal mortality data at all.

“We have an invisible epidemic,” Joy Phumaphi, the WHO’s assistant director-general for family and community health, said in a statement.

The campaign involves more than a dozen international and regional agencies and will focus on 20 high-priority countries.

The WHO said $10 million more was required to fund the initiative.