The clear list
- No periods by age 15.
- No periods within three years of her breasts starting to develop.
- Periods that were established and have now stopped for three months or more.
- Bleeding heavy enough to soak through protection hourly, last more than seven days, or cause tiredness.
- Pain that regularly stops school, sleep or training, or is not controlled by over-the-counter pain relief.
- Bleeding between periods.
- Menstrual changes alongside repeated injuries, a stress fracture, or persistent fatigue.
The one most often missed
Periods stopping in a hard-training teenager is not a normal effect of sport. It is the most common reason a GP visit is needed and the most commonly skipped.
Things that do not usually need an appointment
If you are unsure, a practice nurse or pharmacist is a reasonable first stop, and NHS 111 online can help you decide.
- Unpredictable cycles in the first year or two after periods start.
- Cycles of 21 to 35 days that vary by a few days.
- Mild cramping that responds to pain relief and heat.
- One late period after illness, travel or an exam week.
What to take with you
- Dates of recent periods, even approximate ones.
- Training hours per week across every club, school team and activity.
- How much she has grown in the last year.
- Any injuries, especially bone injuries.
- A note of tiredness, mood, sleep and appetite.
- Any supplements or medication she takes.
What usually happens
Expect a conversation rather than an examination in most cases, covering periods, training, eating, growth and general health. Blood tests are common, typically including full blood count, ferritin, thyroid function and hormone levels.
Depending on the picture, next steps may include treatment for heavy bleeding or pain, iron treatment, a referral to a sports dietitian, a bone density scan, or a paediatric or gynaecology referral.
Getting the most from ten minutes
- Say at the start that she is a competitive athlete training X hours a week.
- Ask directly about energy availability, bone health and iron.
- Ask what would make you come back, and when.
- Offer her time alone with the GP, teenagers often say more without a parent present.