The United Nations said Monday that Afghanistan needs to more than double its midwife numbers to curb one of the world''s highest maternal mortality rates despite a huge increase in practitioners.

"In 2002 there were only 467 trained midwives in the entire country," World Health Organisation country representative Peter Graaff told a news conference.

That number had increased to more than 2,100 by 2008, he said.

But in a stark assessment of Afghanistan''s needs, he said: "The total estimated requirement for midwives in the country is not 2,100 but 4,500... in order to cover the needs of 90 percent of the population."

Afghanistan and Sierra Leone have the second-highest maternal mortality rates in the world, with one in eight women dying in childbirth, according to UN figures. Only in Niger is the rate higher, at one in seven.

About 80 percent of these deaths are avoidable in Afghanistan, Graaff said.

The main causes of death are excessive bleeding, infection, high blood pressure and prolonged or obstructed labour -- all factors that underscore the need for a skilled attendant.

Graaff also said many women deliver outside clinics or hospitals and do not receive pre-natal care.

Girls in Afghanistan often fall pregnant at a young age and commonly marry when they are 15-17 years old, said Catherine Mbengue, country representative for the UN children''s organisation, UNICEF.