WASHINGTON – About 15 million premature babies are born every year – more than 1 in 10 of the world’s births and a bigger problem than previously believed, according to the first country-by-country estimates of this obstetric epidemic.

The startling toll: 1.1 million of these fragile newborns die as a result, and even those who survive can suffer lifelong disabilities. Most of the world’s preemies are born in Africa and Asia, says the report released Wednesday.

It’s a problem for the U.S., too, where half a million babies are born too soon. That’s about 1 in 8 U.S. births, a higher rate than in Europe, Canada, Australia or Japan – and even worse than rates in a number of less developed countries, too, the report found.

But the starkest difference between rich and poorer countries: Survival.

Sophisticated and expensive intensive care saves the majority of preterm babies in the U.S. and other developed nations.