(CNN) The United States continues to be outpaced by smaller countries in its treatment of its mothers, dropping two spots to 33rd place in Save the Children's newest annual global motherhood rankings.

Norway rose to the top of the list while Somalia remained last for the second year in a row in Save the Children's "State of the World's Mothers 2015: The Urban Disadvantage," released Monday evening.

The five indicators in the 2015 Mothers' Index of 179 countries are the lifetime risk of maternal death; children's well-being as measured by their under-5 mortality rate; educational status, as measured by children's expected years of formal schooling; economic status, as measured by gross national income per capita; and political status, measured by women's participation in national government.

Women in the United States face a 1 in 1,800 risk of maternal death, the worst odds of any developed country in the world, according to the report.

American women are 10 times more likely to die of pregnancy related causes than their counterparts in Poland, according to the report. And an American child is as likely to die as a child in Serbia.

With more than half of the world's people now living in cities, the plight of the urban poor is drawing more attention. Within the same city, even in industrialized countries, there's a notable disparity between the rich and poor, Save the Children has found.

In Ward 8, the poorest part of the District of Columbia, babies die before their 1st birthday at a rate more than 10 times higher than babies born in Ward 3, the richest part of the city, according to 2012 data in the report.

The contrast between the top and bottom countries remains stark. While 0.3% of Norwegian children die before their 5th birthday, some 15% of Somali children do. Somali children who survive will get fewer than 2.5 years of formal education, while Norwegian children will get 17.5 years of formal education.

"We need to do more to make sure that all mothers and babies have a fair chance of survival and a happy, healthy life -- no matter where they live," said Carolyn Miles, president and CEO of Save the Children, in a press release.

"Save the Children believes that a mother in Somalia, or frankly a mother in America, deserves the same opportunity to thrive as a mother in Norway."

Save the Children works to improve the lives of children around the world, which includes better nutrition, sanitation, health care and education for mothers and their children.

Best countries for mothers:

Norway Finland Iceland Denmark Sweden

Worst countries for mothers:

Somalia Democratic Republic of the Congo The Central African Republic Mali Niger

One woman in 18 in Somalia will eventually die in childbirth, while one in 20 will die in Niger. One child in seven in Somalia, Chad and the Central African Republic will not live to see his or her 5th birthday.

While the conditions in which many of the world's children live are grim, about 17,000 fewer children die daily versus 25 years ago. And the number of children who die before their 5th birthday has been cut almost in half, from 90 to 46 deaths per 1,000 live births.