In some countries getting pregnant can kill. One is Niger, which comes bottom of Save the Children's Mothers' Index, an annual list of the best and worst places to be a mother. In Niger, one woman in every 30 will die from pregnancy-related causes. In Norway – which, along with Iceland and Sweden, tops the list – the figure is one woman in 7,600.

Save the Children's index tots up a lot of different factors to work out the rankings. They include how much education a woman is likely to get, the difference in earnings between men and women, how easy it is to get contraception, and the number of women lawmakers.

But it all boils down to a simple truth: the poorer a country, the less empowered women are in every way – and the more likely they and their children are to die prematurely.

Bad in every way

Here are the rankings in full – and here are the top and bottom five:

Best places

Norway
Iceland
Sweden
New Zealand
Denmark

Worst places

Niger
Afghanistan
Yemen
Guinea-Bissau
Mali

Afghanistan took the bottom spot in the previous two years. This year, conditions there have improved slightly, for several reasons – a big one being investment in frontline health workers. Meanwhile, the lives of mothers and children in Niger have got worse. That's partly because of famine in the Sahel (the vast arid region south of the Sahara desert, which covers most of Niger): poor nutrition is a primary cause of deaths among mothers and babies.

But what makes Niger exceptional, Save the Children says, is that it scores so badly on every measure of women's welfare. A typical girl in Niger will spend four years in formal education (for a Norwegian girl, it's 18 years); she has a life expectancy of 56 (Norway: 83). Only 5 per cent of Nigerien women use modern contraception, and one child in seven will die before his or her fifth birthday – with the result that on average, every mother in Niger can expect to lose a child. Across the world

Maternal mortality: as American as mom's apple-pie

The United States ranks lower than most developed nations, at 25th in the "Mother's Index" (though that's up six places from last year). One reason is that in the US the poor, especially minorities, lack health insurance and so miss out on prenatal care. A woman in the US is more than seven times as likely to die of a pregnancy-related cause in her lifetime as a woman in Italy or Ireland. Being in a poor country is bad for mothers: being in a rich one doesn't solve all the problems.

Learn more: Read the whole of Save the Children's State of the World's Mothers report.

Take action: Join Save the Children's call to world leaders, asking them to make sure that "every child has a fifth birthday".