Johns Hopkins All Children's Hospital

Puberty For Girls

Helpful information for girls about the different physical and emotional changes that take place during puberty. 

When your child is about 10-12 years old, she'll start to notice different changes happening to her body and emotions. This is all a part of puberty.

As a girl, some of the physical and emotional changes she will start to notice include:

  • Body parts changing or growing. For girls, their breasts will grow and bra size will change.
  • She will start to grow taller, and probably taller than boys in her class during the beginning of puberty.
  • She will start to have hair growing in different parts of her body such as the arm pits and on the outside of the vagina.
  • Her mood might change and she may start to feel different. Some days she will feel happy and have a lot of energy, and some days she may feel more tired and not so happy or even grumpy.
  • The way she thinks about herself and other people might change.
  • She might start thinking more about her future and start to question things happening around her at home, school, in her community or even on the news.

Physical Changes


Most girls grow taller in height during the stage of puberty known as the growth spurt. This usually happens between ages 8-13. This is around the same time that changes in breast size start to happen. Girls usually stop getting taller about 2 years after they have their first period.

Your child may have noticed that by 4th grade, most of the tallest people in her grade were girls. This is because girls usually start their growth spurt before boys do. Even though girls start growing taller before boys, by the time she reaches high school the boys will catch up in height and will probably be taller than most girls by the end of puberty.

It is important for girls to know that everyone grows at different speeds so it is best not to compare themselves to their friends. How much or how fast a person grows depends on their sleep patterns, exercise habits, nutrition, and family genetics.

Breast Development

One of the first signs of puberty for girls is breast changes. Their breasts will start to grow bigger between ages 8-13, and this will happen in stages. At first, they may notice a firm bump, also known as a breast bud, behind their nipples. As their breasts grow, their areolas (the skin around the breast) and nipples will grow as well and may become darker.

It is normal for their right and left breasts to seem uneven as they grow. They may also seem pointy at the beginning but will become rounder and fuller with time. They may feel like their breasts are growing fast or slow. It's important for girls to remember that everyone’s body is different and they do not need to compare their bodies to their friends or people they see on TV. 

Body Hair

As girls go through puberty, one of the changes that they will notice is that they start to grow hair in new places. Girls will grow new hair underneath their arm pits, legs, and around the outside of their vaginas. Sometimes, people like to shave this new hair using shaving cream and a razor. Encourage your child to talk to you before making this decision so that you can show her how to shave safely. 

The hair on her head may change as well and she might notice that her scalp feels oilier. This is because during puberty our hormones start to change and this might cause her sweat glands to make more sweat and natural oils in certain parts of the body, including the scalp. This may mean that she needs to wash her hair more often. Shampoo helps to remove the dirt and any oil that builds up during the day. Conditioner afterwards will help to keep her hair moisturized and shiny. 

All girls are born with unique and different hair texture. Some girls have very soft hair and some girls have very coarse hair. Often times girls with coarse hair only need to wash it every 1-2 weeks.  


Vaginal Discharge

This is a thin, clear, transparent, or whitish fluid that your child may notice in the lining of her underwear. This comes from the reproductive system and vagina and helps to prevent infection, and keep the vagina moisturized and healthy. This is completely normal and natural during puberty.

If your child experiences a sudden change of color or smell of the vaginal discharge talk to your child's doctor to make sure she doesn't have an infection. All girls are unique and different and some girls have more vaginal discharge than others. Some people may choose to wear a thin pad or panty-liner. 

There are a few things to keep in mind to help prevent vaginal infections:  

  • Your child should always wipe from front to back after going to the restroom. This keeps from spreading germs towards the vagina. 
  • Have your child avoid using scented soaps or body washes because these can cause irritation and increase the risk for infection. 
  • If your child has to take antibiotics for a long time, an infection may be more likely to occur, so be aware of any changes that may happen. 


Sweating is good because it helps to regulate our body temperature. During puberty, your child's body begins to produce smellier sweat. Why this change? The body has two types of sweat glands: eccrine glands and apocrine glands. The eccrine glands have been working since we were born, but when puberty starts the apocrine glands begin working. This sweat causes a body odor because it reacts with the bacteria on the skin.

It is very important that your child shower daily and doesn't forget to wash under her arms and in the groin area. She should also start to wear deodorant or antiperspirant under her arms every day, and should reapply deodorant after physical activity or as needed throughout the day. It may be a good idea for her to keep extra deodorant in her locker or backpack to use after PE class. There are many different kinds of deodorants and choosing the right one depends on her body and preferences.  


Remind your child to brush her teeth at least twice per day. As she gets busier with school, activities, and homework, this can be easy to forget, but brushing her teeth will keep them healthy and cavity-free. It also keeps the teeth whiter and the breath smelling fresh. Your child should brush her teeth for two minutes and start at her gums and work her way around all of the teeth.  

After brushing, your child should also floss her teeth at least once per day. Small pieces of food and bacteria can get stuck in between the teeth. Flossing is a really important way to keep from getting cavities, gum infections, and bad breath. 


Showering daily helps clean away any dirt and oil build-up from the day. Showering often will keep your child feeling and smelling fresh and also prevent body odor and some acne. 

Understanding Periods

Starting her menstrual cycle, also known as a period, can be a confusing, scary and exciting time for girls. Remind your child that getting her period is a sign that her body is maturing and preparing to be an adult woman.

Here are a few answers to common questions she may have about periods:

When will I get my period? 

Girls typically get their first period between the ages 9-15.  

How long will my period last? 

Periods last anywhere from 2-7 days and happen every 21-34 days. It is normal for periods to skip a month during the first two years of starting. If your period lasts longer than 7 days, talk to your doctor.  

What will my period look like? 

Your period flow can be thick, lumpy, or runny. It can be brown, pink, or different shades of red. The amount of flow for a typical period is between 4-6 teaspoons.  

Are periods painful? 

You may have belly cramps, feel tired or have headaches before and during your periods. These symptoms are commonly known as premenstrual symptoms or PMS. You can take ibuprofen, do some light exercise and stretching, or use a heating pad on your belly to help ease discomfort. Talk to a doctor if your period pain gets in the way of school, studying, or sleep. 

Should I use pads or tampons? 

You should use whichever product you are most comfortable with. Pads and tampons should be changed every 3-4 hours. If you are soaking through a product in an hour or less you should speak with your doctor.  

Emotional Changes

Mood Changes and Sleep

As she goes through puberty, she may begin to have more mood swings. One minute she may feel happy, and then the next minute, she may feel sad. This is normal and happens because of hormone changes during puberty.

Your child should be aware of how these mood swings affect her and those around her. When she starts to feel overwhelmed, encourage her to try to find healthy and safe ways to cope and manage these feelings. She can try things like taking a walk outside, talking to a friend, doing an activity to express herself, or exercising. Encourage her to talk to a trusted adult like a parent, school counselor, or doctor, and most importantly, remember that she is not alone.  

Premenstrual syndrome (PMS) are symptoms that girls may have starting 14 days before their next period. They are caused by changing hormone levels and include breast tenderness, food cravings, backaches, and cramps. One of the most well-known symptoms can be moodiness. Remind her that the best thing to do is to be aware that this may affect her mood, and that it is not OK to use PMS as an excuse to act disrespectfully.  

Sleep plays an important part in our moods. When your child is tired, she may be cranky, irritated, more emotional, and less likely to think through her decisions. Therefore, it is very important for children to get enough sleep. As a pre-teen, your child should be getting at least 9-12 hours of sleep a night.  

Having good sleep habits is extremely important. Your child can try things like:  

  • Make sure she has a consistent bed time (even on the weekends). Her body will get used to the routine, and it will get easier to fall asleep and to wake up. 
  • Don’t use electronics, like a cellphone, for at least one hour before bed time.  
  • Keep her room cool, dark, and quiet. 

More information for boys and girls

Learn more about other topics for boys and girls, including nutrition, exercise, sleep, dealing with acne, developing strong relationships with family and friends, social media safety, and more.

Learn more

Still have questions? Come see us.

Our pediatric and adolescent medicine teams have special training to meet the unique needs of children, pre-teens and teens. We're here to help guide you and answer any questions you might have.

The information here is not intended to be nor should be used as a substitute for medical evaluation or treatment by a health care professional. This publication is for information purposes only and the reader assumes all associated risks.

Content expert: Jasmine Reese, M.D., M.P.H.