Women in their 30s and 40s are more willing to engage in a variety of sexual activities to capitalize on their remaining childbearing years, according to a new study.

The results show women ages 27 to 45 have a heightened sex drive in response to their dwindling fertility.

Such "reproduction expediting" includes one-night stands and adventurous bedroom behavior, the research shows.

"Our findings suggest that women don't need to necessarily go 'baby crazy' in their 30s or go around thinking they're supposed to be having a 'sexual peak,'" said study researcher Judith Easton, a psychology graduate student at the University of Texas at Austin.

"Our results suggest there is nothing special about the 30s, but that instead these behaviors manifest in all women with declining fertility," Easton said. "It may be more difficult to conceive past the age of 35, but our research suggests women's psychology will continue to motivate them to try until menopause."

The researchers recruited 827 women from the University of Texas at Austin and from Craigslist.com. Most of the participants, 661, had no children.

The women were split into three groups: high fertility (ages 18 to 26); low fertility (27 to 45): and menopausal (46 and up). The respondents answered an online questionnaire about their sexual attitudes and behavior.

Compared with the other groups, women in the low-fertility group were more likely to experience:

Frequent sexual fantasies

Thoughts about sexual activities

More intense sexual fantasies than their younger counterparts

A more active sex life and willingness to have a one-night stand

A greater willingness to have casual sex

Contrary to their predictions, the researchers found that both low- and high-fertility women (excluding menopausal women) who were in relationships fantasized equally about their current romantic partners and other people.

According to a 2010 report from the Pew Research Center's Social & Demographic Trends, mothers of newborns in all race and ethnic groups are now older than their counterparts 20 years ago. Fourteen percent of births in 2008 were to women ages 35 and older, and 10 percent were to teens.

With more women having children past their peak childbearing years, Easton says the research will have implications on reproductive and sexual health issues, such as fertility, sexual dysfunction and marital development.

The results will be published in an upcoming issue of the journal Personality and Individual Differences.