What is the Average Age to Get Your First Period?

People who menstruate are getting their first periods earlier than our historical friends. Why is puberty happening at a younger age, and when can you expect your first period?


Pop quiz: What is the normal age to get your first period?

*Aggressively loud buzzer noise*


Trick question! There is no “normal” age to get your first period! Bodies are all unique and different, and what might be considered the norm for one body can be totally different for another (download our free period guide to learn more). There are average age ranges to expect things like puberty (and yes, your first period), but remember these are just averages. It doesn’t mean everyone is going to fit exactly within that range. There are a TON of factors that can play into when your body will decide it’s ready to begin puberty and start menstruating. Let’s talk about a few of them: 


What is the average age to get your first period?

On average, people who menstruate have been getting their first period earlier than those throughout history. Today, the average age to get your first period is when you’re about 12.5 years old. In 1928, the average age for Americans to get their period was 13.9. In the 1950s and 60s, this number dropped to 13.5, then to 12.8 in the 1970s. Jumping waaay back in the history books, the average age for first periods used to be even later. In the Victorian Era (the 1800s,) the average age was about 14, and during the Renaissance (1300s-1600s) the average age was about 16 years old. 


Download the Kt free period guide


So, I only need to be on the lookout for my first period after my 12th birthday?

Ah, if only navigating puberty was that easy. As rude as it is, there’s no manual for how to navigate puberty, teenhood, or periods – including when to expect your first one. (Honestly, there isn’t even a manual for navigating adulthood. We really are all just out here.) Remember, 12.5 is just an average age to get your first period. Some people might get their first period at ages 9, 10, 11, or 12, others might get theirs at 13, 14, 15, or 16. In some circumstances, some people experience something called precocious puberty, which is when puberty begins before the age of 8 or 9.  


Why is the average age for first periods earlier than it used to be?

To be super honest, I don’t know. No one really does. However, scientists have a few ideas: 


Obesity and early puberty

Last year, the World Health Organization stated obesity had nearly tripled since 1975, and 39 million children under the age of 5 were overweight or obese in 2020.

But what does obesity have to do with periods? 

Estrogen is stored and produced by the fat cells in our bodies. So, an increase in fat cells naturally means more estrogen in your body. Estrogen is also what makes your uterine lining thicken. When the lining of your uterus thickens and isn’t fertilized with an egg (AKA you are not pregnant), it will begin to shed and voila: you get your period. Long story short, higher obesity rates in young people may be a reason the average age for puberty is beginning earlier. While every body is different and weight gain can be caused by a whole whack of reasons, a good rule of thumb for people at every age is to eat healthily, exercise plenty, and speak with your doctor if you have any concerns.


Environmental factors

Environmental factors may also be contributing to earlier starts of puberty. There isn’t a huge amount of data surrounding this theory, and the data that does exist isn’t entirely clear. However, we do know that we are all exposed to tons of different chemicals daily, mainly through the air, and they can speed up the puberty process–including welcoming your first period to the party.  Pollutants in the air are much more excessive than they used to be, (the ol’ horse and buggy didn’t exactly emit as much gas as a new SUV). There are also so many different kinds of pollutants in the air that scientists can’t pinpoint exactly which chemical might be causing periods to arrive earlier. (Just another reason why sustainable, green practices are the bee’s knees.) 

Image via Instagram (@tonyfutura) 


Can stress cause periods to start earlier? 

Chronic stress may also be linked to kick-starting puberty early. Chronic stress is perceived by the brain as a low-grade threat, which triggers the brain to start reproduction. 

Say whaaaaat?

So, you’re saying my older sibling needs to stop stressing me out or else I’ll start my period sooner?

Not exactly. Chronic stress isn’t the same kind of stress that’s related to homework or friends (or your older brother bugging you). While these things could play a part, chronic stress is when you feel pressured and overwhelmed for a long time. Something like your parents going through a divorce might (but not always) be a trigger for chronic stress. If you’re going through something difficult or experienced something traumatic, harmful or abusive, always speak with someone you trust like a parent, teacher, or counsellor. You never have to suffer alone, no matter what you’re going through–chronic stress or not. 


Hey parents/guardians! Make sure you always have an open line of communication with your children. If you think something might be wrong, ask!  Create a safe space where your child feels comfortable voicing their concerns and feeling heard. 


Image via Instagram (@littledrill) 


Some signs you might be getting your first period soon 

Some of the classic signs of puberty include body hair, your chest growing/getting fuller, and an increase in sweat. There are a few other key signs your period is coming, and plenty of pro tips to make sure you’re prepared for when it does (including how to put in a tampon for the first time, and environmentally friendly period products). 

No matter when you start your first period, remember that what’s going on with your bod is completely normal. If you think something irregular is going on, make sure to always speak with your doc. To be ready for anything, try wearing a pair of KT’s Leakproof Underwear so you won’t be caught off guard. And most importantly always remember, you got this. :) 

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