Menstruation: definition and meaning
Menstruation is the monthly shedding of the lining of the uterus, which leaves the body through the vagina as blood and tissue. It is commonly called a period. It happens when an egg isn't fertilized and hormone levels fall. A period usually lasts 2 to 7 days and comes every 21 to 35 days in adults.
Why menstruation happens
Each cycle, estrogen and progesterone build up the endometrial lining so a fertilized egg could implant. If no pregnancy happens, progesterone falls, the lining breaks down and is shed. That shedding is menstruation, and day one of it is day one of your menstrual cycle.
What's typical
| Typical range | |
|---|---|
| First period | Usually between ages 10 and 15 |
| Cycle length | 21 to 35 days in adults, up to 45 in teens |
| Bleeding days | 2 to 7 |
| Blood loss | About 2 to 3 tablespoons (30 to 40 ml) over a period, up to about 80 ml |
| Last period | Around age 51, at menopause |
Period blood can be bright red, dark red or brown, and small clots are normal. Period products range from pads and tampons to menstrual cups and period underwear.
Menstruation and mood
Mood across a period varies. Many people feel relief as PMS lifts, others feel tired or low on heavy days. If mood changes before a period are severe enough to disrupt life, it may be PMDD.
See a doctor if periods are very heavy or painful, last over 7 days, stop for 3 months, or you bleed between periods or after sex.
Frequently asked questions
Is menstruation the same as a period?
Yes. Menstruation is the medical word, period is the everyday one. See period.
How many periods does a person have in a lifetime?
Roughly 400 to 500, depending on age at first period and menopause, pregnancies and contraception.
Is it normal for my period to change over time?
Yes. Periods often settle in the years after puberty and change again after pregnancy and in perimenopause. Sudden big changes are worth a check.
Sources
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Period: definition and meaningA period is the monthly bleed when the uterine lining sheds, also called menstruation. What's normal for length, flow and timing, and when to get help.
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.
Menstrual phase: definition and meaningThe menstrual phase is the part of your cycle when you have your period, usually days 1 to 5. What happens to hormones, energy and mood during it.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.
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.