Every additional month of paid maternity leave is associated with a 13 percent reduction in infant mortality rates in low-income countries and the developing world, a recent study suggests.

That translates into eight infant deaths averted for every 1,000 births.

Earlier studies have linked paid time off after birth with lower infant mortality rates in affluent nations, but the current study offers the first look at how paid leave may influence survival for babies in less wealthy countries, researchers report in the journal PLoS Medicine.

"Our findings suggest that extending the duration of paid maternity leave is a potential instrument for reducing infant mortality in low- and middle-income countries, particularly those that offer shorter durations of leave, and achieving global targets to eliminate preventable child deaths," said lead study author Arijit Nandi, a health and social policy researcher at McGill University in Montreal.

Paid leave is connected to a range of health benefits for mothers and babies including reduced rates of postpartum depression, more breastfeeding and increased follow-through with routine infant checkups and immunizations, previous research has shown. Fathers, too, stand to gain, with some research suggesting they develop stronger bonds with their children when they're paid to stay home.

For the current study, Nandi and colleagues examined data on about 300,000 children born over eight years in 20 low-income and developing nations across Africa, Asia and Latin America.

They combined health statistics for the children with information on government maternity leave policies in each country.

On average, about 55 in every 1,000 babies died during the study period. Mortality during what's known as the neonatal period, or the first month of life, was about 31 babies per 1,000 births. From age 2 months to 1 year, the mortality rate was about 23 babies per 1,000.

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Reductions in infant mortality associated with longer paid maternity leave primarily happened after the first month of life.

The study can't prove that paid leave directly lowers infant mortality, although the results do account for individual, household and country-level characteristics, the authors note.

One limitation of the analysis is that researchers relied on mothers to recall the timing of births and deaths of children who weren't alive at the time they provided data for the study. The research team also looked only at government leave policies, which may not always reflect the amount of paid time off women actually received.

Among countries that account for 95 percent of maternal and child deaths, just one third reached last year's Millennium Development Goal of reducing child mortality by two-thirds, the authors write.

Worldwide, more than 180 countries guarantee some type of paid leave for new mothers, though the U.S. isn't among them, they note.

Leave policies are becoming more generous for some workers who live in U.S. states that require paid time off or who work for companies with generous paid time-off benefits.

This week, for example, Twitter said all its employees will soon qualify for five months of paid leave. Last year, Facebook announced that all employees worldwide would get four months of paid parental leave, and Netflix said it would offer up to one year of paid leave after the birth or adoption of a child.

Last week, New York became the fifth state to mandate paid leave, passing a budget agreement giving most employees in the state up to four months off after the birth, adoption or fostering of a child, or to care for a sick relative. New York joins California, New Jersey, Rhode Island and Washington. San Francisco this week became the first U.S. city to guarantee new parents paid time off.