The first period.

A first period can bring pride, worry, surprise or very different feelings. Your child needs a simple explanation and practical support.

Understanding the situation

Period blood contains blood and tissue from the lining inside the uterus. It leaves the body through the vagina. The first bleeding may be light and look brownish or red.

At first, the time between periods can vary. The brain and ovaries take time to develop a more regular pattern of communication, and ovulation may not occur in every cycle. A period shows that the body has progressed further through puberty. Your child still needs age-appropriate care and information.

The first period usually occurs some time after breast development has begun. Timing varies between children. It is useful to discuss both ordinary differences and signs that should be assessed, so your child receives support without unnecessary worry.

Research and further reading for adults

What does recent research tell us about the timing of the first period?

For readers who want more detailed scientific information. These studies describe patterns in large populations and cannot predict an individual child's health.

Read about the studies and what the findings mean

A Norwegian systematic review and meta-analysis published in 2025 pooled 783,757 observations from people born between 1840 and 2008. It found that the average age at first menstruation has decreased over time. For birth cohorts after 1950, the decline was much slower than before, at approximately 0.7 to 1 month per decade. The study concerns trends in the age at first menstruation, not breast cancer risk among Norwegian girls.

A 2026 systematic review and meta-analysis combined 74 case-control studies on age at first menstruation and breast cancer. In the pooled analysis, having a first period before age 13 was associated with higher odds of breast cancer later in life (OR 1.15; 95% confidence interval 1.08–1.24). This is a statistically significant but relatively modest association at population level. An odds ratio does not represent an increase of the same number of absolute percentage points.

These are observational studies. In addition, the breast cancer analysis uses unadjusted odds ratios from the individual studies. The results show an association but do not establish that early menstruation itself causes breast cancer. An early first period is neither a diagnosis nor a prediction of an individual child's future health.

For parents, the priority is to understand their child's development, provide knowledge and reassurance, and contact healthcare professionals when development, bleeding or other symptoms warrant assessment. There is no reason to burden your child with long-term risk figures that cannot reliably say anything about them personally.

Read the original studies

Turning knowledge into action

What you can do

Show your child how to use a pad and let them choose products they feel comfortable with.
Make a small school-bag kit with period products and spare underwear.
Ask whether your child would like help noting when bleeding occurs.

Find a way to start

One way to begin

“If your period starts at school or somewhere else, we can make a plan to help. What would be useful for you?”

Use your own words and give your child time to respond. A short conversation can be a good beginning.

More help with the conversation

Further support

When should you seek help?

Contact a doctor for severe pain, heavy bleeding or if a first period has not occurred by age 15. Vaginal bleeding before ordinary pubertal development should be assessed.

See who you can contact

Continue learning

Periods and menstrual cycles

Understanding the menstrual cycle

Periods and menstrual cycles

When periods are painful

Sources and further reading

Sources were checked on 13. October 2026. The conversation examples are suggestions from Tidlignok.

This content provides general information. Healthcare professionals can assess your child's symptoms, circumstances and treatment needs.