Growing up: Information for girls about puberty
What is puberty?
Puberty is a time when your body goes through many changes—you’re growing both physically and emotionally from a child into a teenager and eventually into an adult.
Although puberty doesn’t happen at the same time for everyone, it usually starts between 8 and 13 years for girls. It isn’t something that happens overnight, but a process that takes place over several years.
To help you understand, this is how your body works:
- Puberty is controlled by hormones, which are natural chemicals made in your body. The hormones that are important during puberty in girls are made in the brain and in the ovaries.
- Your ovaries are two small glands that lie on either side of your uterus. Starting at puberty, your ovaries release one or more tiny eggs each month.
- Your uterus is a small organ in your lower abdomen near your bladder. When a woman becomes pregnant, this is where the baby grows.
- Fallopian tubes are tube-shaped structures that lead from the ovaries to the uterus. They carry the eggs released from your ovaries to your uterus.
- The hormones made in the ovaries are called estrogen and progesterone. They are responsible for most of the changes that will happen in your body during this time.
Changes to your body will happen gradually, over many years:
- First your breasts will start to develop. This starts with just a little swelling under the nipple. It will take several years to reach your full adult breast size.
- Your body grows more curves and your hips and thighs get a bit wider. It’s normal and healthy for you to gain weight while going through puberty.
- You will start growing hair under your arms, on your legs and in your pubic area.
- You will also grow in height. This “growth spurt” happens very quickly. On average, girls grow about 3 inches (8 cm) per year during the growth spurt. Girls usually stop growing taller about 2 years after starting their menstrual period.
- Your genes (the code of information you inherited from your parents) will decide many things during this time, including: your height, your weight, the size of your breasts and even how much hair you have on your body.
What is menstruation?
Usually about 2 years after your breasts begin to form, you will have your first menstrual period. During menstruation (also known as your “period”) you will bleed from your vagina. Some girls get their first period as early as 9 or 10 years old, while others do not get it until later in their teens.
- A “cycle” is the amount of time from the start of one menstrual period to the start of the next. Most girls have menstrual cycles that last anywhere from 21 to 35 days. The bleeding part of the cycle usually lasts a week or less.
- When you first start to menstruate, your periods may not be regular. You might have a few periods that are 30 days apart, and then a couple of months without a period at all. This is normal. It can take up to 2 years for your cycle to become more regular.
- The amount of blood that comes out of the vagina (menstrual “flow”) is different for everyone. Although you could never measure it, the amount of flow is pretty small—anywhere from a few spoonfuls to less than a ½ cup of blood.
Each menstrual cycle follows this pattern:
- An egg gets ripe and is released by one of your two ovaries. This is called ovulation.
- In the days before ovulation, estrogen increases and causes your body to develop a thick uterine lining that is made of blood and tissue. This is how the uterus gets ready for a possible pregnancy.
- If you have sex around this time and the egg is fertilized by sperm, it will travel to the uterus and attach itself to the cushiony wall. Then it slowly develops into a baby.
- If the egg is not fertilized, it doesn’t attach to the wall of the uterus. The uterus doesn’t need the extra tissue lining, so it sheds it.
- The blood, tissue and unfertilized egg leave the uterus, going through the vagina on the way out of your body. This is your period.
Menstruation is a normal, healthy part of being a woman and shouldn’t affect your day-to-day activities. You can still participate in sports and activities. Exercising may even help relieve the pain and discomfort of cramps. Some medicines, like ibuprofen can help ease the pain of cramps. If your cramps are so painful that they stop you from doing other things, like going to school or hanging out with friends, talk to your doctor.
Are there other changes I can expect?
- More sweat. Since sweat can cause body odour, it helps to take a bath or shower every day.
- Some girls develop acne (pimples). Washing your face in the morning and at night with regular, fragrance-free soap and water is important. If you do get pimples, acne lotions, creams and special soaps may help. If they don’t work, talk to your doctor about other treatments.
- Attractions. Many people start to be romantically and sexually attracted to others during this time.
Will I feel different?
Not only do hormones cause physical changes in your body, they can also affect how you feel. Emotions during puberty may feel a bit like a roller coaster. You may:
- Be afraid of the changes in your body one minute and excited about them the next.
- Feel awkward or confused.
- Laugh one moment and cry the next.
- Get along and fight with good friends all in the same day.
- Feel angry at times.
- Feel grown up one day and like a child the next.
Sometimes, these changes can be overwhelming. You’re not alone. Like other teens, you’re going through a period of transition in your life. It can be both scary and exciting at the same time.
How can I take care of myself during puberty and throughout life?
Your changing body needs sleep—lots of it. Puberty takes up a lot of energy. Most teens need at least 9 hours of sleep each night. Some need even more.
Food and exercise
Since a growing body needs food, you will often be hungry. Eating a balanced diet that includes all food groups and being physically active are important to your health. Try to make physical activity part of your daily routine. Here are some ideas to get you started:
- Be active and spend less time on screens.
- Walk more—to school, the mall, a friend’s house.
- Use the stairs instead of the escalator or elevator.
- Walk the dog, rake the leaves, or shovel snow (your parents will thank you).
- Do activities you enjoy: skating, swimming, biking, running. etc.
- Follow the Canada Food Guide.
If you are worried about your weight, or want advice on healthy living, talk to your doctor. Your doctor can suggest a healthy eating and exercise program for you to follow.
What else should I do?
- Puberty can cause you to have lots of different feelings and emotions. Talk to people you trust, including your parents who have been through this before. This can help you cope with the changes you are experiencing.
- Stay away from alcohol, drugs and tobacco. All of these can harm your body and are addictive.
- Talk to someone you trust about healthy relationships and attractions.
- Use social media safely.
More information from the CPS
Reviewed by the following CPS committees
- Adolescent Health Committee
- Public Education Advisory Committee
Last updated: March 2018