It can make you think you like a guy. Lower estrogen levels during your period can increase your "male cognitive skills," such as spatial thinking, according to Pauline Maki, Ph.D., associate professor of psychiatry and psychology at the University of Illinois at Chicago. This doesn't mean you'll start obsessing over fantasy football, but your map-reading skills may peak along with your period.
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There's no need to bleed. While some women think extended-cycle birth-control pills (the ones that put your period on hiatus) are the greatest things since chocolate-covered pretzels, others worry about tweaking Mother Nature. Relax, says Mary Jane Minkin, M.D., clinical professor in the department of obstetrics and gynecology at Yale University School of Medicine: "Your uterus won't explode if you don't have a period." Extended-cycle pills give you 28 days of hormones, rather than 21 plus seven placebo pills, so there's no hormonal vacay week of bleeding. In fact, you can benefit from taking any kind of birth-control pills. Studies show they decrease your risk of ovarian cancer by about 50 percent.
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Stress can make a period more—or less—frequent. Not only can stress wreck your sleep—it can also throw a wrench into your cycle, says F. Ralph Dauterive, M.D., chairman of obstetrics and gynecology at Ochsner Clinic in Baton Rouge, Louisiana. "Your brain responds to nerve-racking events by releasing stress hormones that can interfere with those regulating your cycle, setting you up for irregular periods, shorter cycles, or even menses that go MIA for months at a time."
It can make you crave sex. Though you may be more inclined to reach for your comfy sweats over lacy lingerie, a lot of women find themselves turned on during menstruation. Since the level of progesterone—the hormone that some experts blame for putting a damper on libido—is at its lowest during your period, you might feel frisky, Minkin says. More good news: Researchers say frequent boot knocking and being exposed to hormones in male armpit sweat (no, you don't have to sniff it) can lead to more regular cycles.
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