The West African state of Niger is the worst place in the world to be a mother, according to Save the Children. The ranking comes in the charity's annual index which compares conditions for mothers in 165 countries. It considers a number of factors including health, education, economic status and nutrition. Niger is severely affected by a regional food crisis. It replaces Afghanistan at the bottom of the Save the Children index. After two years at the bottom of the list, Afghanistan has moved up a notch. This is credited to greater investment in front-line health workers. 'Vicious cycle' This year the situation in Niger reflects the impact of nutrition. The food crisis developing in the Sahel region is threatening the lives of up to a million youngsters, Save the Children says. The charity describes how chronic malnutrition leads mothers, who themselves have been stunted in childhood, to go on to have underweight and vulnerable babies. It warns that if a mother is "impoverished, overworked, poorly educated and in poor health, she may not be able to feed the baby adequately, with largely irreversible effects". Director of policy Brendan Cox said: "We urgently need global leadership on malnutrition that results in key nutrition projects being rolled out for mothers and babies to ensure health and survival." Save the Children believes that measures focusing on the first 1,000 days of a child's life, starting from pregnancy, could help to break the vicious cycle. BBC Africa analyst Martin Plaut says the Save the Children report shows that wealth is not the sole criterion for a nation's position in the survey. He says a poor country like Malawi has done significantly better than might have been expected for one key reason: Children are breastfed by their mothers within an hour of their birth and continue to be breastfed for up to two years. Our correspondent says Nepal, Pakistan and Mali have trained tens of thousands of health visitors to roll out best practice and, as a result, breastfeeding has risen and the number of poorly nourished children has fallen sharply. Save the Children identifies Norway as the best place to be a mother, while the UK comes 10th. Meanwhile the UN has appealed for urgent funding to help provide food assistance to almost 4 million Nigeriens and 160,000 Malian refugees in Niger as the Sahel region enters the "lean season". According to the World Food Programme and UN refugee agency, the impact of the successive droughts in Niger, very high food prices and crop failures has been compounded by an influx of refugees fleeing political unrest in neighbouring Mali.