When it comes to first periods, there’s an incredible range of things that are considered normal. The earliest age that a period will usually arrive is 8 (though evidence suggests that young girls are getting  periods earlier and earlier) and the latest is usually around 17. The average age for a girl to get her first period is 12 years old. However, age is not a guarantee and there is no specific time when your daughter or child will get their period. If you begin to notice your daughter or child having mood swings or feeling anxious, it may be a sign that they are beginning to enter puberty and their period will be arriving soon. If you’re wondering when your child will get their period, the best thing to do is just be patient and not stress too much. If you're still concerned about when your daughter will get her period, then talk to a health professional.

What is a normal age for girls to start their periods?

The average age for girls to begin puberty is 11-12 years old. However, some girls start as early as 8 years old and others as late as 16 years old or even older. It’s important to note that this is based on averages and does not apply to all girls or boys who experience puberty at different times.

There's no way to know exactly when your daughter will start her period. But physical signs of puberty, such as  breast buds, hair growth under the arms, and an increase in height and weight, are typically a good indicator. Body size can play a role, as girls with bigger bodies tend to get their periods earlier. 

The first period is often referred to as a “menarche,” from the Greek word for “month.” Girls usually begin menstruating regularly around two years after breast development begins. Puberty typically begins around or after your child's tenth birthday. It's a time of great change for both boys and girls—but it can be tough for parents to watch.

Causes of delayed menstruation in young girls 

If your child or daughter has reached their mid-late teens without getting a period they may be experiencing delayed menstruation which can be caused by a number of factors. These include:

1. Hormonal imbalance

A hormonal imbalance (e.g. too much or not enough estrogen) is one relatively common cause. This is typically caused by polycystic ovarian syndrome (PCOS), which is a condition that affects the ovaries and can cause irregular periods and infertility. A doctor can diagnose PCOS by performing blood tests and a pelvic exam.

2. Being underweight 

If your child is underweight, it may be affecting their body’s ability to produce hormones thereby delaying their period. The body requires enough stores of fat in order to produce estrogen, which is needed for ovulation. If you’re concerned that your daughter is too thin, talk with her doctor about how much weight she should gain over time as she gets older.

3. Too much exercise 

Excessive exercise can prevent ovulation from happening, which is why so many athletes have irregular periods. Lack of period is a common problem among dancers, gymnasts, and other athletes who train six days a week or more. When girls exercise too much without fueling their bodies adequately, they can stop ovulating. Similar to being underweight, the body needs enough fat to produce estrogen and other hormones required for ovulation. If you’re concerned that your daughter is exercising too much, talk with her doctor about how many hours of exercise she should have each day.

4. Eating disorders 

The most obvious sign that your daughter may be suffering from an eating disorder is if she has suddenly lost a great deal of weight, engages in restrictive eating practices or refuses to eat anything at all. If this happens, consult with a doctor or therapist and talk with her about why she’s lost so much weight and how it might affect her menstrual cycle.

5. Severe stress 

The stress hormone cortisol can inhibit ovulation, so if your daughter is under a lot of stress, she may not get her first period until those hormone levels go down. For example, if she recently went through a breakup or suffered some other major trauma in her life, it could take several months before her body recovers enough for her menstrual cycle to return to normal. Other sources of stress may include problems at school or parents going through a divorce. Any number of these factors might be disrupting her body’s ability to produce hormones. Talk with your daughter about why she feels so stressed out and find some ways that you can help her handle these issues. 

Methods to determine when a young girl has started her period

Make sure you have an open and honest rapport with your daughter or child so that they feel comfortable talking to you. Once those lines of communication have been established, you will be the first person they want to talk to when their period arrives. Another, though less accurate, way to determine if your child has started their period is to be on the lookout for signs and symptoms of puberty. If you notice your child acting moody, irritable or withdrawn, they may be going through changes due to puberty.

Tips for parents on how to deal with the 'period talk' with their daughters

Dealing with the 'period talk' can be a daunting task, but it is important to understand that this conversation sets the stage for healthy and comfortable conversations about your daughter's body, her health and her sexuality as she grows up. 

Explain how periods work 

First off, give her the basic information that explains what is going on inside her body. (If you need a refresher, download Kt’s free period guide for a primer on puberty.) That way she can lead the conversation by asking any questions she may have. Be sure to explain important aspects like how to put in a tampon, so she feels prepared to have a period going forward.

Don't be awkward

It is important that, as a parent, you are able to discuss menstruation in an open, comfortable and honest manner. For example, what is a medium flow period vs a heavy flow? A sense of ease will show your child that menstruation is nothing to be afraid of and ensure they are more likely to embrace the information you give them. Prepare yourself for this conversation, because the more practiced you are the more comfortable you will be. Perhaps start with a general question like 'What do you know about menstruation?' and then go on from there.

Create a Judgment-free Zone

Be careful not to use any language or reinforce any stereotypes that play into the stigma around periods. For example, refer to natural processes and body parts by their proper names. Euphemisms send the message that the subject matter you are discussing is embarrassing when in reality,  there is nothing embarrassing about periods at all. Other things that can breed shame around menstruation involve calling periods “dirty” or “unclean” or being secretive with information.

Ways to prepare your daughter for her first period 

• Talk to her early and often about puberty. The earlier you start talking to your daughter about puberty, the more comfortable she’ll be when it comes time for her first period. 
• Foster a positive attitude. Stay upbeat when you're discussing the subject and treat their period as something to get excited about rather than a dreaded "curse."
• Share books, websites and apps that explain how menstruation works and what it means for girls’ bodies.

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To download the guide in Canada, click here.