Young adult women in the U.S. who lived through the "Great Recession" may think twice about having a baby, even when the economy bounces back.

About 151,000 U.S. women who were in their early 20s in 2008, when the economic downturn began, will forgo having children as a result, according to a new study published in the Proceedings of the National Academy of Science. The lack of pregnancies could result in some 427,000 fewer births over the next two decades, at least up to age 40.

The impact won't cause great harm to the population. Those postponing pregnancy represent only a small percentage of the 9 million women who were ages 20 to 24 in 2008. America also sees some 4 million babies born every year.

The study's results do show "a pretty profound effect on some women's live," study author Janet Currie, a health economist at Princeton University, told The Associated Press.

Currie conducted the study with her colleague Hannes Schwandt. The researchers used birth records and census data to track the births of every American-born woman up to age 40 from 1961 to 1970, according to the AP. The total number of women accounted for was about 18 million people.

The researchers then compared the time of babies' conceptions to unemployment levels at the time. They could only track conceptions that led to live births.

The results showed poor economic times could discourage these younger women to take on the added financial responsibility of having a child. Also, they may be less likely to try for a baby later on, according to the authors.

Women in older age groups did not show the same results.