Period: definition and meaning
A period is the bleeding that happens when the lining of the uterus sheds and leaves the body through the vagina, usually once a month. It is the everyday word for menstruation. Periods typically start between ages 10 and 15, last 2 to 7 days, and come every 21 to 35 days until menopause.
Why periods happen
Every cycle your body prepares for a possible pregnancy by thickening the lining of the uterus. If no egg is fertilized, hormone levels drop and the lining is shed. The first day of bleeding is day 1 of your menstrual cycle. For the medical side, see menstruation.
What's normal
- Length: 2 to 7 days of bleeding
- Gap: 21 to 35 days from the start of one period to the next (up to 45 in teens)
- Flow: heavier for the first day or two, then lighter
- Color: bright red, dark red or brown; small clots are normal
- Feelings: cramps, tiredness and mood changes are common in the days before and during
Read more in how long does a period last, period blood colors and period cramps.
Periods and mood
For many people, the hardest emotional days come before a period, during PMS, and lift once bleeding starts. Others feel low or tired on heavy days. Neither is a character flaw: it's hormones and biology.
See a doctor if your period lasts over 7 days, soaks through protection every 1 to 2 hours, stops for 3 months, or the pain stops you from doing normal things.
Frequently asked questions
Why is it called a period?
Because it comes at a regular interval, or period of time, roughly once a month.
Can you get your period twice in a month?
Yes, if your cycle is short, for example 21 to 24 days. See two periods in one month.
When will my period come?
Add your usual cycle length to the first day of your last period. Our period calculator does it for you.
Sources
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Menstruation: definition and meaningMenstruation is the monthly shedding of the uterine lining through the vagina, known as a period. Why it happens, how long it lasts, and what's normal.
Menstrual cycle: definition and meaningThe menstrual cycle is the monthly hormone cycle that prepares the body for pregnancy. Its four phases, normal length, and how it shapes mood.
Period calculator: when is my next period?Free period calculator: enter the first day of your last period and your cycle length to see your next 6 periods. Private, instant, nothing is stored.
How long does a period last?How long does a period last? Usually 2 to 7 days, about 5 on average. What changes it, how much blood is normal, and when a long period needs a doctor.
What actually happens during your period?What happens during menstruation: hormones fall, the uterine lining sheds, and the uterus contracts to push it out. Why we have periods and what's normal.