Women's Health

When Your Period Signals a Problem

As you probably learned back in middle school, menstruation is the monthly shedding of your uterine lining. Though it can be uncomfortable and sometimes inconvenient, your period is your body's way of telling you that your reproductive system is working properly. 

Just as every woman is unique, every woman's period has its own personality. Some periods are short, others are long. Some are heavy, others are light.

After a few years' worth of monthly bleeding, most women start to get a feel for their period's frequency, duration, and flow. When something out of the ordinary happens -- such as spotting between periods or an exceptionally heavy flow -- it's natural to wonder what's going on.

Is There Such a Thing as a Normal Period?

Not really. The average woman's menstrual cycle is 28 days long, and the average period lasts for three to five days, but there can be huge menstrual cycle variations from woman to woman.

"Three days is normal for some women, seven days is normal for others," says Franklin Loffer, MD, executive vice president and medical director of AAGL (formerly known as the American Association of Gynecologic Laparoscopists). Similarly, the normal period flow can be heavier in some women than in others.

Rather than worrying about the length or frequency of your period, you need to consider whether anything has changed.

"A woman should really be tracking her own menstrual cycle, because it provides huge numbers of clues about whether something's not right," says Frances Ginsburg, MD, director of reproductive endocrinology at Stamford Hospital in Stamford, Conn., and assistant professor of clinical obstetrics/gynecology in the Columbia University College of Physicians and Surgeons. 

Here are some common menstrual period changes, and what they might mean.

Your Period Has Slowed or Stopped

The big question if you're not getting your period is -- how old are you?

The cause of a missing menstrual period (called amenorrhea) varies by age. "To quit having periods at age 25 is a significantly different issue than quitting at age 50," Loffer says. 

For a woman in her 20s or 30s who is sexually active, pregnancy is always a possibility. "Even if a woman thinks she's protected, that's not an absolute guarantee," Loffer says.

On the other hand, women in their 40s or 50s could be in perimenopause -- the period surrounding  menopause. As your ovaries slow their estrogen production, periods become less frequent. Periods also can get shorter or lighter during perimenopause. Once your periods stop for a full 12 months in a row, you're in menopause.  The average age for menopause is 51.

Another possible cause of missed periods is excessive exercise. Anywhere from 5% to 25% of female athletes work out so hard that they stop getting their periods. Called exercise-induced amenorrhea, this phenomenon is particularly common among ballet dancers and runners. Intense exercise affects the production and regulation of reproductive hormones involved in the menstrual cycle.