Carrying a pack of menstrual pads in your school bag when you’re only eight years old? Perfectly normal. At least, if the trend of girls getting their period at an increasingly younger age continues. What does science says about this?

Menstruating earlier and earlier

While in 1900, the average age of menarche – the age at which girls first menstruate – in Western Europe was still between 14 and 15 years, in 2000 it had already dropped to 12.4 years. This decline is happening all over the world: a Korean study shows that the average age of menarche there has dropped from 16.9 years (for women born between 1920 and 1925) to 13.8 years (for women born between 1980 and 1985).

American research from 2024 shows a similar decrease. In the Apple Women’s Health Study, 71,341 women of different ages reported when they first got their period. They also gave information about their origin, socio-economic status, BMI and the time it took for their menstrual cycle to become regular.

In this study, menarche age was divided into categories: before age 9 is defined as ‘very early’, before age 11 ‘early’ and after age 16 is considered ‘late’. What did they find? The younger the women, the earlier they had their menarche. Participants born between 1950-1969 were on average 12.5 years old, with 8.6% of them in the ‘early’ category and 0.6% in the ‘very early’ category. The younger women, born between 2000-2005, had their menarche at an average age of 11.9 years. Of these, 15.5% had their period early (before age 11) and 1.4% very early (before their ninth birthday).

Main cause: obesity 

There are several reasons why girls are getting their period at an increasingly younger age. It’s known that your genes, but also your living conditions, such as your diet, play a major role. Research from the United Kingdom from 2024 identified no fewer than 1,080 signals in DNA that influence the age of menarche. Just under half of these genetic variations already cause weight gain in childhood and thus lead to an earlier menarche. A study among Chinese children from 2023 showed that a late bedtime and short sleep duration leads to an earlier puberty.

Often, it’s a combination of factors that causes early menarche: for example a lack of sleep, stress, obesity and a poor diet. Nowadays, environmental influences such as air pollution (a Polish study and an American study – both from 2023 – show a link between air pollution and early menarche) and hormone-disrupting chemicals are also included as possible causes. Other possible causes are childhood trauma and family problems (which cause stress). Even the lockdown during Covid-19, and the stress that came with it, may be linked to earlier puberty, according to an Italian study. The aforementioned Apple Women’s Health Study shows that especially girls from low-income households and racial minorities start menstruating earlier.

Will this trend continue? Scientists aren’t sure yet. It’ll largely be up to society. Will the number of girls with obesity, stress and lack of sleep continue to grow and will there also be an increase in hormone-disrupting chemicals in our care products and air pollution in our cities? Then a few decades from now it might be totally normal to get your period in primary school. However, if we as a world population all start eating healthier, exercising and sleeping more, and taking better care of the environment, it’s quite possible that the average menarche age will slowly increase again.

What are the risks of an early menarche?

Girls aren’t only getting their periods younger, it’s also taking longer for their menstrual cycles to become regular. The Apple Women’s Health Study reported that the percentage of women who had regular cycles within two years of menarche had dropped from 76% (among women born between 1950-1969) to 56% (among women born between 2000-2005).

It’s of course annoying to already get your period when you’re only ten years old. But is it a bad thing? Well, yes. Because early menarche comes with significant health risks. There’s for example a higher chance of breast cancer, type 2 diabetes and heart disease later in life. Girls who get their period before the age of twelve are 23% more likely to develop breast cancer than girls who get their period after the age of fifteen. They also stay smaller (after menarche you grow a maximum of four inches) and are more likely to become obese later in life.

Apart from the physical, there are also psychological consequences. For very young girls it can be confusing to already have to deal with menstrual pads – your body is becoming an adult when your mind is still a child. That’s why we need more education. There’s no point in learning about menstruation in high school when you’ve already started your periods in primary school. Now is the time to learn about periods. The responsibility for menstrual education starts of course at home. It doesn’t have to be complicated. Read a book. Watch a menstrual animation. Visit a menstruation museum. Or play an educational game. Put menstruation on the agenda before you have to put menstrual pads into the school bag.

Period! is an independent, online magazine about all aspects of menstruation. Period! is not intended as a substitute for medical advice. If you’re suffering from medical complaints, always visit your doctor or GP. Editorial articles can contain affiliate links. Sponsored collaborations can be found in the category Spotlight. Do you have any questions? Check our Contact page.

Also read:
No more periods. Help?
Menstruation gone wrong
When is a lot, too much?
Too little: also possible?
How to overcome your fear of gynaecological examinations