One of the most important measures of a country's quality of life, along with per-capita income and longevity, is infant mortality — the odds that a newborn will live past its first month. By that measure, America is slipping into second-tier status, ranking 41st among 193 nations, tied with Croatia, Qatar, and the United Arab Emirates, according to a study recently published in the journal PLoS Medicine. Two decades ago, the U.S. ranked 28th. Here, a brief guide:

Is America really doing so badly?
It depends how you look at it. The U.S. has 4.3 deaths per 1,000 live births, or almost 20,000 newborn deaths each year. But newborn mortality rates are actually improving here. "It's not that things are worse in the United States than before," says pediatrician Dr. Joy Lawn, as quoted in USA Today. It's just that other countries are advancing faster, so babies born in countries like Malaysia, Cuba, Lithuania, and Poland now have a better chance of survival than those born in the United States. 

What is causing newborn babies to die?
There are three major culprits: Preterm delivery, asphyxia (lack of oxygen), and infections. Each of these is easily preventable. "Training more midwives and other community health workers could save the lives of many more babies," says Lawn, who works with the nonprofit Save the Children. "We know that solutions as simple as keeping newborns warm, clean, and properly breastfed can keep them alive."

Where is the problem of newborn death worst?
Afghanistan and Somalia tie for last place, with a rate of 53 deaths for every 1,000 live births, according to the report, sponsored by the World Health Organization. In terms of sheer numbers, India, Nigeria, Pakistan, China, and the Democratic Republic of the Congo account for half of the world's 3.3 million newborn deaths each year, mostly because of those country's immense populations.

Which countries fare the best?
Japan has a very low rate of 1.1 newborn deaths per 1,000 live births. Next are Singapore, Cyprus, Sweden, the Czech Republic, and Finland, all with newborn mortality rates equal or better than 1.8 deaths per 1,000 live births. 

Sources:, PLoS, PBS Newshour, TIME, USA Today