Menstruation is the time of month when a woman's womb (uterus) sheds its lining, causing bleeding through the vagina. Menstruation periods usually last about 3 to 5 days, but every woman is different. Follow the links below to find WebMD's comprehensive coverage about menstruation, how it occurs, when you should see a doctor, and much more.
Why Is My Period So Random? Why Irregular Periods Happen
Many women have irregular periods. How "off" is yours?
Think You Know Your Period? 5 Surprising Facts
No matter how well you think you know your favorite monthly visitor, it can still manage to surprise you from time to time.
What’s a Normal Menstrual Period?
Periods can be long and short, heavy and light. And it's all considered normal.
All About Menstruation
Menstruation doesn't need to be a mystery. Learn more from WebMD about puberty and starting your period.
When Your Period Signals a Problem
Pain, bleeding, and missed periods may be signs that something is wrong.
Period Problems: What They Mean and When to See the Doctor
The Monthly Bill. The Woman's Curse. The nicknames we give to the monthly shedding of the uterus lining reflect the troubles it brings. So how do you know what's normal and what's not?
Birth Control Pills That Reduce Monthly Menstruation and Periods
The newest birth control pills suppress women's menstrual cycles. But is this wise?
The New No-Period, No-PMS Birth Control Pills
With new continuous birth control pills, women can end their menstrual periods and reduce PMS symptoms.
How Your Menstrual Cycle Affects Your Sleep
How does your menstrual cycle affect your sleeping patterns? Sleep expert Michael Breus, PhD, has answers.
What Is a Normal Menstrual Cycle?
Laura Corio, MD, explains a normal menstrual cycle.
Period Tricks for Teens
Tips and tricks of the trade on dealing with your menstrual cycle.
Teenage girls unravel the myths and mysteries of menstruation.
Slideshows & Images
Answers to Your Top Period Questions
Get answers for your period and menstruation questions. See what’s normal and what’s not for missed periods, flow, and more. Plus, PMS coping tips.
What Your Period Says About Your Health
Some things about your period -- like heavy flow and type of cramps -- offer clues to problems in your body. Find out what's normal and when to see the doctor.
What's Your Menstrual Pain IQ?
Test your knowledge of relieving menstrual pain caused by endometriosis, fibroids, or other factors.
Is My Period Normal?
Quiz: Is My Period Normal? Period symptoms can be painful and perplexing. Take this quiz to learn when to do something about problems like an irregular period, and how to help PMS.