"A lot of adolescents get these 'blow out' periods, and they have no idea that they're too heavy -- or that there are things they can do to help control them," said McGuire. "They just assume that everyone's [period] is this way." While having a heavy flow is relatively common (and most women tend to bleed more in the first few days), if you find yourself needing to change your pad or tampon more than every two to three hours, or if your period lasts longer than seven days, it's likely time to talk to a health care provider about your options. Hormonal birth control can help decrease the amount of flow a woman experiences, as can certain pain relievers. There's also a small chance that heavy flow is a sign of menorrhagia , a term used to define periods that are so intense, they keep a woman from doing her usual activities. The bottom line -- if you think your flow is abnormally heavy, ask!

For women who have painful periods (and evidence suggests there's a lot of us out there), getting relief from cramping and other common physical symptoms often requires taking over-the-counter pain relievers before any bleeding even starts. "If you take [medication] when the symptoms are already bad, you're behind the ball," said McGuire. "If your periods are pretty regular, and if you know you start on a Wednesday or Thursday, for example, I might start dosing on a Tuesday." Research also suggests that certain lifestyle changes -- like getting plenty of exercise and sleep, eating healthy foods and finding ways to relax -- can help provide some women with some relief.

"In most instances, your period should not keep you from your normal activities," said Dr. Mary Rosser, an assistant professor and attending physician in obstetrics and gynecology at Montefiore Medical Center in the Bronx. "Studies have shown that 90 percent of women will experience some symptoms, [but] mostly mild. And 10 to 20 percent will have symptoms that interfere with normal activities." Those symptoms can crop up when you're actively bleeding, or as a part of PMS, which occurs because of hormonal changes in the week or two prior to your period. See your doctor if you have you have cramps that keep you from doing your normal, daily activities, or PMS symptoms that interfere with your day-to-day.

It's highly unlikely, but it is possible for you to become pregnant during your period. As Health.com explains , some women have long periods that overlap with the beginning of ovulation -- even though they're still menstruating. Or, as Dr. Michele Hakakha, an OBGYN and author of Expecting 411: Clear Answers and Smart Advice for Your Pregnancy, told Parents.com : "A woman with a shorter menstrual cycle (24 days, for example), could have seven days of bleeding, have intercourse on her final day of bleeding and ovulate three days later. Since sperm live for three to five days, she could definitely get pregnant."

5. You Have Your Own Discharge Pattern -- And It's More Complex Than You Think.

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When it comes to the complete menstrual cycle, every woman has a slightly different pattern. However, most women bleed, then are dry for a few days, then experience a light, mucus-like discharge (pre-ovulation) that becomes increasingly cloudy and thick (a sign that ovulation has likely ended). "What's different from one woman to another is the quantity of discharge," McGuire said. "It's just like how some people have oily skin, and others have dry skin." Clueing into your own pattern is just good practice, namely so you have a sense of what is happening in your body and can watch out for any changes.