Children born in developing countries this year will lose more than $177 billion in potential lifetime earnings because of stunting and other delays in physical development, scientists said on Wednesday.

Children who have poor growth in their first years of life tend to perform worse at school which usually leads to poorer earning power later on.

The Harvard scientists calculated that every dollar invested in eliminating poor early growth would yield a $3 return.

"$177 billion is a big paycheck that the world is missing out on - about half a percentage point of GDP of these countries," said Peter Singer, head of Grand Challenges Canada, which funded the research through its Saving Brains program.

"We have to stop wasting the world's most precious economic and social asset and ensure children thrive."

Poor nutrition, premature birth, low breast-feeding rates and early exposure to infection are among several causes of stunting which affects three in 10 children in the developing world.

World Bank President Jim Yong Kim recently warned that childhood stunting was "a great unrecognized disaster", adding that countries which failed to invest in early child development would be left behind in an increasingly complex, digital world.

First in-depth study

Echoing his remarks, Singer said the economic value of investing in children's early years was "absolutely humongous".

"In an age of essentially stagnant growth, ignoring this issue is the dumbest thing you could do for the global economy, while paying attention to this issue would be one of the smartest," he told Reuters.

Scientists at the Harvard T.H. Chan School of Public Health said their research represented the first in-depth study of the economic impact of poor early growth in low - and middle-income countries.

Progress in improving early childhood physical development has been slow compared to the significant achievements in reducing under-five mortality rates, the report said.

The Harvard scientists arrived at the $177 billion figure after looking at indicators for the 123 million children born in 2010 in 137 low and middle-income countries.