Menarche

Menarche (pronounced “muh-naar-kee”) is the medical word for getting your first period.

When it happens, tissue from the inside of your uterus flows out of your body through your vagina. It mainly looks like blood. But it can vary in color (from pink to brown). Its texture can vary too — from thin and watery to thick and jelly-like.

This milestone is a part of puberty. It’s one way your body physically becomes an adult. Your period is a natural and healthy sign that your body is working as it should.

When do girls get their periods?

Everyone is different. The average age of the first period is 12 years in the United States. But this can vary. You may get it sometime between the ages of 9 and 15 — or later.

Many things affect when your first period happens. But it’s common to get it at around the same age your biological mother did.

It can also help to think back to when you noticed changes in your breasts (when puberty started). Your first period usually happens about two years after your breasts begin to grow.

What is its purpose?

Your first period marks the start of your reproductive years. This is the time in your life when your body can have a pregnancy — a baby. Your reproductive years last from the time of your first period to your later 40s, on average.

You may be wondering why a period has to happen at your age. There’s no clear answer to this, unfortunately. It’s just part of being a human female and a natural part of growing up.

What causes menarche?

Hormone changes cause your first period. Hormones are chemical messengers in your body.

You get your first period when your body has grown enough to support a menstrual cycle. A menstrual cycle is your body’s way to prepare for a possible pregnancy each month. Hormones in your brain and sex organs control this cycle.

Each month, hormones make your ovaries release a tiny egg. The lining of your uterus builds up. If you have penis-in-vagina sex, sperm can fertilize the egg. A fertilized egg then sticks to your uterus lining. Here, it grows into a fetus. This is a pregnancy.

If there’s no sperm, fertilization doesn’t happen. Your uterus doesn’t need a thickened lining anymore. It gets rid of the egg and lining through your vagina. This is your period.

You can think of it like cats and dogs shedding a layer of fur once winter ends. They don’t need that extra fur to stay warm, so their body gets rid of it. Your uterus gets rid of its thickened lining every month when it doesn’t need it to support a pregnancy.

How do I know I’m getting my first period?

In the days leading up to your first period, you may notice:

• Pain or achiness in your lower belly or lower back (cramping)
• A full or swollen belly (bloating)
• Tender or sore breasts
• An increase in pimples (acne)
• Mood swings
• Tiredness

During your first period, you may:

• Notice red or brown blood on your underwear or on toilet paper when you wipe
• Only see a few spots of blood by the time your period ends
• Have light bleeding at first that gets heavier, and then becomes light again
• Have period bleeding that lasts for two to seven days

Everyone experiences periods differently. Don’t worry if your period is different from a classmate’s. If you’re unsure about what’s normal, talk to an adult you trust. This could be a parent, teacher or doctor.

How does menarche affect my body?

Your first period means it’s possible to get pregnant if you have penis-in-vagina sex. Always using birth control when you have sex helps prevent this.

Your body may keep growing after menarche. But your first period typically happens toward the end of puberty. This means you’ll have gone through most of the changes puberty brings by the time you get your first period.

What conditions are related to your first period?

If you have any of these issues during your period, it’s important to tell a caregiver:

• Having quarter-sized or larger blood clots in the period blood
• Soaking through a pad or tampon every hour for at least two hours
• Bleeding for more than 10 days
• Severe cramping that keeps you from your usual activities

These are signs that something isn’t right.

Sometimes, your first period can arrive earlier or later than expected:

• Early puberty and menarche: You get your period before age 9.
• Amenorrhea: You haven’t gotten your period by age 15.

See a healthcare provider if either of these situations applies to you. They can try to find what’s causing it.

How do I take care of myself?

Getting your period comes with extra tasks. You’ll have to do more to care for yourself and keep track of your health.

It can be annoying or a bummer. But you don’t have to stop doing the things you love just because you get your period. And no one has to know that you’re on your period unless you want them to.

Getting your period means learning about:

• Period products
• How to manage symptoms
• Tracking your period

Period products

There are many ways to manage blood flow during your period. It may take time to find the best product for you. You can change your method at any time. Period products include:

• Pads or panty liners: You may use pads for heavier period days (more bleeding) and panty liners for lighter days (less bleeding). Change pads or panty liners at least every four to eight hours.
• Tampons: Tampons soak up the blood from your vagina before it leaves your body. You can swim during your period when you’re wearing one. Change tampons at least every four to eight hours.
• Menstrual cups: You put a menstrual cup in your vagina to collect the blood. They can usually hold more blood than regular tampons. Empty and wash the cup every eight to 12 hours.
• Period underwear: This is special underwear that soaks up period blood. It’s washable and reusable. You may just wear the underwear. Or you may use them with other period products.

Your first period — and the ones after it — may catch you by surprise. So, it can help to be prepared. You may want to carry a period care kit that includes:

• Pads and/or tampons
• A pair of underwear and/or pants
• A sweatshirt you can tie around your waist

Managing symptoms

If cramps are bothering you, a few things that can help include:

• Taking a warm bath
• Gentle exercise and stretching
• Placing a heating pad or warm washcloth on your belly
• Taking medicines that contain ibuprofen (Advil® or Motrin®) or naproxen (Aleve®)

Don’t take aspirin for cramps unless your healthcare provider says it’s OK. Aspirin may not be safe for children under 18.

Tracking your periods

It’s a good idea to begin tracking your periods on a calendar. Tracking them can help you learn what’s normal — and what’s not — for you.

A typical menstrual cycle happens every 21 to 35 days (28 days on average). It usually lasts for two to seven days (five days on average). But everyone’s period is different.

You can mark on your calendar when your period starts. You could even use a symbol or emoji to make it more discreet if you want. You could then count ahead 28 days or so and leave a mark so you have an idea when your next period may start.

For the first year or two, your periods may be unpredictable. You may have months when you skip a period as your body adjusts to a regular cycle.

As your period gets more regular, you can learn what’s normal for you. And you can recognize when bleeding or your schedule is different. Abnormal bleeding is a sign that you should see a healthcare provider.