[Skip to Content]

All About Periods

Medically reviewed by: Krishna Wood White, MD, MPH

A period is when blood comes out through a girl's vagina. It is a sign that she is getting close to the end of puberty. Puberty is when your body goes from looking like a kid's into looking more like a grown-up's.

There is a lot to learn about periods. Here are some common questions that kids have.

When Do Most Girls Get Their Period?

Most girls get their first period when they're around 12. But getting it any time between age 10 and 15 is OK. Every girl's body has its own schedule.

How Will I Know My First Period Is Coming?

There are some signs that a girl's period may start soon. These include:

  • She's worn a bra for a few years.
  • She has hair under her arms and in her private parts.
  • She has some clear, stringy liquid (called discharge) coming from her vagina.

Why Do Girls Get Periods?

A period happens because of changes in hormones in the body. Hormones give messages to the body. These hormones cause the lining of the uterus (or womb) to build up. This gets the uterus ready for an egg (from the mom) and sperm (from the dad) to attach and grow into a baby. If the woman does not get pregnant, the lining breaks down and bleeds. This same process happens every month. That is why most girls and women get their periods around once a month.

Do Periods Happen Regularly When Menstruation Starts?

For the first few years after a girls starts her period, it may not come regularly. This is normal at first. By about 2–3 years after her first period, a girl's periods should be coming around once a month.

How Long Do Periods Last?

Periods usually last about 5 days. But a period can be shorter or last longer.

How Often Does a Period Happen?

Periods usually happen about once a month. But some girls get their periods around every 3 weeks. And others only get a period about once every 6 weeks.

Should I Use a Pad, Tampon, or Menstrual Cup?

There are a few ways to deal with period blood. You may need to experiment a bit to find which works best for you. Some girls use only one method and others switch between different methods.

  • Most girls use a pad when they first get their period. Pads are made of cotton and come in lots of different sizes and shapes. They have sticky strips that attach to the underwear.
  • Many girls prefer to use tampons instead of pads, especially when playing sports or swimming. A tampon is a cotton plug that a girl puts into her vagina. Most tampons come with an applicator that guides the tampon into place. The tampon absorbs the blood. Don't leave a tampon in for more than 8 hours because this can increase your risk of a serious infection called toxic shock syndrome.
  • Some girls prefer a menstrual cup. To use a menstrual cup, a girl inserts it into her vagina. The cup holds the blood until she empties it.

How Much Blood Comes Out?

Although it may look like a lot of blood, a girl usually only loses a few tablespoons of blood for the whole period. Most girls need to change their pad, tampon, or menstrual cup about 3–6 times a day.

Will I Have Periods for the Rest of My Life?

When women are around age 45‒55, they stop having periods (this is called menopause). Women also won't have a period while they are pregnant.

What Is PMS?

PMS (premenstrual syndrome) is when a girl has emotional and physical symptoms right before her period starts or during the early part of her period. A girl with PMS might:

  • be in a bad mood
  • feel more sad or worried than usual
  • feel bloated (swollen)
  • gets pimples

Do All Girls Get Cramps?

Lots of girls have cramps with their period, especially in the first few days. If the cramps are very uncomfortable, a warm heating pad on the belly and medicines can help.

Looking Ahead

Periods are a natural, healthy part of a girl's life. They shouldn't get in the way of exercising, having fun, and enjoying life. If you have questions about periods, ask your doctor, a parent, health teacher, school nurse, or older sister.

Medically reviewed by: Krishna Wood White, MD, MPH
Date reviewed: October 2018