Can you put a price tag on moms' stress from kids?

It's well established that having children costs parents a tidy bundle, thanks to expenses for food, education, clothing and childcare.

But what about the intangible issues that parents face when their new baby arrives, such as the stress of sleepless nights or the time crunch when trying to juggle work, kids and home life? According to three economists who tackled the question, the stress cost is unbelievably high, especially for women, with mothers feeling three times the time stress of their husbands.

The study relied on data from Australian and German surveys that each tracked thousands of heterosexual married couples for about a decade, asking questions such as, "How often do you feel rushed or pressed for time?" The economists found that Australian mothers' annual incomes would have to rise by about $66,500 to compensate for the added stress after the birth of a child. Although the effect was somewhat smaller in the German study, but still significant, at about $48,000 annually.

"I would have liked something smaller or more reasonable, but that's the way the dice fell," said Daniel Hamermesh, an economist at the University of Texas at Austin, who is one of the paper's authors. "This is a serious problem. The theory we base on it is that stress is an indicator of making you worse off."

The idea that parenting is stressful is well understood, but assigning a dollar figure to what the economists call the "stress cost" of kids is a novel approach to consider the impact of childbirth. Previous studies have considered whether parents are happier than non-parents (it's not entirely clear), while other studies have found that parents feel less satisfied with their relationships.

Then there's the impact to the lifelong earnings of fathers and mothers. Unfortunately, women are generally getting the short end of the stick when it comes to the impact of parenting on their wages. After having a child, women experience lower lifetime earnings than their childless peers, with the average high-skilled woman losing $230,000 in lifetime wages as a result, according to a 2010 paper from researchers at Columbia, Harvard and New York University.

Men, however, are rewarded monetarily after starting a family, with a University of Massachusetts, Amherst sociologist finding that men receive a pay bump of about 6 percent after becoming a father.

But less tangible has been the impact of stress on mothers versus fathers, as well as how to assign a financial measure to the time crunch. The study may reassure men that fatherhood will only slightly impinge upon their lifestyles, with the economists finding that the time stress on fathers, smaller to begin with, fades after the child's first year. For women, however, the time stress continues. (The studies tracked parents for the first four years after a child's birth, so it's possible that mothers' time stress does fade after that.)

The research comes at a time when women are not only working more, but they're also still managing the lion's share of childcare and household duties. In households with children under 6 years old, women spend about one hour providing physical care to kids, compared with just 26 minutes for men, according to the American Time Use Survey.

Hamermesh noted that when he talks with people about the results of his research, mothers and fathers aren't particularly surprised. "The guys say, 'Well, that's the way it is,' and the women grimace and say, 'Yeah, we know that'," he said. He added that the research suggests that societies should reexamine the gender roles in child-rearing. "Women bear the cost, so maybe [men] should do more to lessen the time stress on women," he noted.

It could be that becoming a parent, especially for women, is growing less appealing for adults, given the cost to one's time, money, and career. In some industrialized countries, birthrates are declining. While the U.S. population continues to increase, the Census Bureau last year said that growth had slowed to 0.71 percent, or the slowest since 1937. The birthrate for American women in their 20s fell 15 percent between 2007 to 2012. The U.S. baby dry-spell might be over, however, with preliminary figures showing that American births rose last year, the first increase in seven years.

When one considers both the hit to one's bank account and the spike in stress from having kids, it might make one wonder why people -- and especially women -- actually take the plunge into becoming parents. It boils down to issues beyond dollars and cents, Hamermesh noted.

"People are rational enough to realize that it's very stressful, but they still do it," he said. "You do it to leave something to posterity."