The National Bureau of Economic Research (NBER) published a report early this week demonstrating a correlation between national conception rates and economic recessions. According to the report, pregnancy rates have dropped prior to economic downturns several times over the last few decades, indicating that they can predict the economic trajectory.

The report calls the findings a “new business cycle fact”, stating that the “the growth rate of conceptions declines prior to economic downturns and the decline occurs several quarters before recessions begin.”

“Our findings suggest that fertility behavior is more forward-looking and sensitive to changes in short-run expectations about the economy than previously thought,” the report explains. “The (2008) recession began in December, as later determined by the NBER, and by this time conceptions had already been in decline for months,” the report said. It adds that all normal economic indicators were positive in 2007. Consumer confidence was high and the stock market was strong, too.

Conception growth rates changes before the collapse of Bear Stearns and Lehman Brothers, as well.

“Bear Stearns did not collapse until the end of the spring of 2008. Several months later, in September of 2008, Lehman Brothers collapsed, an event sometimes considered a catalyst in the great recession,” the economists noted. However, conception rates in the first three quarters of 2008 were already 100,000 lower than those of 2006, and falling.

“Once you examine monthly or quarterly data, the pattern becomes obvious,” said one of the study’s authors Daniel Hungerman. “We show the existence and magnitude of this pattern before the Great Recession, and it’s striking since that recession was famously hard to predict. None of the experts saw it coming,” he said, “And in its first few months, many business leaders were convinced the economy was doing OK — even as the number of conceptions plummeted and had been falling for a while.”

According to the report’s data, conception rates predict upcoming downturns more accurately- and earlier- than GDP growth rates.