New York City Mayor Michael Bloomberg said on Tuesday he is funding the expansion of a pilot maternal health program in Tanzania that is predicted to help 50,000 mothers and their children during the next three years.

A woman dies every two minutes of pregnancy-related problems with 99 percent of such deaths in poor countries, according to the U.N. Population Fund. Common causes are bleeding after childbirth, high blood pressure, infections and unsafe abortions.

"No one should have to die giving birth," Bloomberg told a news conference at the United Nations with Tanzanian President Jakaya Kikwete. "Too many women die due to complications in childbirth because of inaccessible and inadequate care."

The Bloomberg Philanthropies initiative trains assistant medical officers and midwives in remote areas to perform life-saving procedures including caesarean sections and upgrades isolated health centers.

"If you can build a model that you can show works in remote areas where the doctor to patient ratio is 1 to 50,000 then you can start attracting capital from an awful lot of other foundations and perhaps governments," said Bloomberg, founder of Bloomberg LP who has so far donated more than $2.4 billion to charity.

While U.N. data shows maternal deaths globally halved between 1990 and 2010 to 287,000 annually, many states in sub-Saharan Africa are forecast to fail to reach a U.N. target of reducing maternal deaths between 1990 and 2015 by 75 percent.

Tanzania is not on track to meet the U.N. target and has the eighth highest number of maternal deaths in the world - a woman dies almost every hour. Kikwete said that more money was needed to tackle the problem.

"We need to scale up efforts because still too many mothers and children continue to die," Kikwete told reporters.

The Bloomberg Philanthropies maternal health program began in Tanzania in 2006. Bloomberg has now joined forces with Geneva-based H&B Agerup Foundation to spend $8 million to expand the program over the next three years, taking the total spent since the initiative started to $15.5 million.

Bloomberg's third term as New York City mayor finishes at the end of next year and he has said he will then dedicate himself to philanthropy. He hit No. 10 on Forbes latest ranking of the richest people in the United States with an estimated fortune of $25 billion.

In 2011 Bloomberg Philanthropies spent $330 million and Bloomberg has signed up to the Giving Pledge, a philanthropic campaign by two of the world's richest men - Warren Buffett and Bill Gates - that required him to announce he would give away at least half his wealth during his lifetime or after his death.