Washington, Oct 5  More than one million infants die worldwide every year because they are born too early, according to a recently released White Paper, The Global and Regional Toll of Preterm Birth.

The document shows that in 2005 an estimated 13 million babies were born preterm -- defined as birth at less than 37 full weeks of gestation.

That is almost 10 percent of total births worldwide. About one million deaths in the first month of life (or 28 percent of total newborn deaths) are attributable to preterm birth.

The highest preterm birth rates in the world were found in Africa followed by North America (US and Canada), says the White Paper.

"Premature births are an enormous global problem that is exacting a huge toll emotionally, physically, and financially on families, medical systems and economies," says Jennifer L. Howse, a doctor and president of March of Dimes, a leading non-profit organisation for pregnancy and baby health.

"In the US alone, the annual cost of caring for preterm babies and their associated health problems tops $26 billion annually."

The new white paper uses data published recently in The Bulletin of the World Health Organisation (WHO).

March of Dimes says the WHO Bulletin figures are conservative, counting only singleton preterm births, and probably underestimates the true magnitude of the worldwide crisis of preterm birth.

The toll of preterm birth is particularly severe for Africa and Asia, accounting for more than 85 percent of all cases.

Comparison of preterm birth rates across world regions finds the highest rate in Africa -- 11.9 percent or about 4 million babies each year; followed by (in descending order) North America, Asia, Latin America and the Caribbean, Oceania (Australia and New Zealand combined), and Europe.

Key factors contributing to this increase include a rise in the number of pregnancies in women over age 35, the growing use of assisted reproduction techniques.

Babies who survive a preterm birth face the risk of serious lifelong health problems including cerebral palsy, blindness, hearing loss, learning disabilities and other chronic conditions. (IANS)