CAIRO, Egypt -- Egypt's fertility rate, which has been falling since at least 1980, has risen dramatically in the last six years, according to the results of a new survey released Monday to The Associated Press.

The news raises serious economic concerns for the Arab world's most populous country, whose economy has been staggering since its 2011 revolt.

The survey, conducted jointly with Egypt's Ministry of Health and Population and a U.S. Agency for International Development-funded organization, said the number of births per woman has increased from 3 to 3.5 since 2008. Egypt's fertility rate had been steadily decreasing since at least 1980, when the survey began.

"It's a stunning result," said John Casterline, a professor at the Ohio State University who focuses on fertility rates. Casterline said it is extremely unusual for a country's fertility rate to suddenly increase after decreasing for years.

Researchers say the reasons behind the striking uptick are largely unclear.

"It's probably related to female education and labour participation," said Samer Atallah, an economics professor at the American University in Cairo. He said that there has not been a substantial increase in female labour participation during this past period.

The survey also showed a small, 2 per cent decrease in the use of contraceptives, including both modern and traditional methods. The survey said 3 per cent fewer women obtain contraceptives from public health facilities compared to 2008.

The primary effect, Casterline said, is that "this keeps the Egyptian population young." The challenge will be putting young people through school and eventually creating jobs in an already-stretched labour market with high unemployment, he said.

"The births today, they have consequences for decades," he added.

Atallah agreed.

"Given that we do not invest substantially in education, given that we do not invest substantially in health care systems or facilities, it's going to be a very difficult task to turn this fertility rate around to something positive," Atallah said.