Teen Girls’ Menstrual Cycles Are Different — And It Impacts Their Sport

Why Coaches and Parents Need to Understand Early Periods

For many girls, getting their first period (menarche) is a major developmental milestone and it’s also a time of big physical, emotional, and performance-related changes.

Menarche typically occurs between ages 9 and 15, with the average around 12–13 years. During the first few years after this point, menstrual cycles can be irregular, symptoms can be intense, and performance in sport may feel unpredictable.

Yet this stage is often misunderstood or dismissed, especially by adults who haven’t experienced it recently, or at all.

• Mothers and female coaches may forget what those early years felt like.
• Fathers and male coaches may not feel equipped to talk about it at all.
  
  

Understanding how the menstrual cycle works during adolescence, and how it differs from adult patterns, is a crucial part of supporting female athlete development.

What’s Normal in the Early Years of Menstruation?

For the first 1 to 3 years after menarche, adolescent girls typically experience:

✅ Irregular cycles — Cycles can vary between 21 and 45 days and everything in between, with each cycle potentially being different. This unpredictability is normal as hormone levels adjust.
✅ More intense symptoms — Cramping, heavy bleeding, and fatigue are common. These may be more pronounced in younger teens due to increased sensitivity to hormonal changes.
✅ Emotional shifts — Lower confidence, fear of leakage, and self-consciousness can lead girls to avoid sport, especially during their period.

🔎 In fact, 6 in 10 ‘sporty’ girls say they avoid participating in sport during their period (Sport England, 2018).

By around the third year post-menarche, most girls develop more regular cycles — typically every 21–35 days — similar to adult women. But until then, cycle irregularity and symptoms can make sport participation more challenging.

What Coaches and Parents Can Do

Supporting young female athletes doesn’t require complex solutions, just small, consistent actions that help girls feel safe, seen, and supported.

Here’s how to make a real impact:

✔️ 1. Normalize the conversation

Create an environment where periods are not taboo. Whether you’re a male coach or a parent, simply acknowledging this topic can break down embarrassment and make girls feel more comfortable coming to you.

“Is there anything you need today?” can go a long way.

✔️ 2. Encourage girls to track their cycles

Even if cycles are irregular, basic tracking can help girls notice patterns over time, when they feel strong, when they feel low, and how their symptoms affect their sport.

Use free apps or simple calendar tracking as tools to help them understand their own body.

✔️ 3. Be prepared: pads, tampons, toilets

Keep spare period products in your gym bag or coach’s kit, and tell girls they’re there. Make sure they have easy access to toilets at training and competitions.

This simple step helps reduce stress and makes sport participation feel manageable, not intimidating.

✔️ 4. Offer flexibility in training

Let girls know it’s okay to modify or adapt training when symptoms like cramps or heavy bleeding occur. What feels like a “small deal” to you might be the reason she wants to sit out today.

Empowering girls to listen to their bodies can boost trust and long-term motivation.

✔️ 5. Promote light movement and recovery

Some girls may find gentle movement helps reduce symptoms. Encourage options like walking, stretching, or light training instead of a full session, and always prioritise rest, quality sleep, and whole food fueling.

Final Thoughts

Periods are a normal (and vital) part of female athlete development. But the early years can feel overwhelming, especially when symptoms are strong and confidence is low.

By understanding that early menstrual cycles are not the same as adult cycles, we can better support young girls to stay active, involved, and confident in sport.

💡 The key takeaway?
Unpredictability is normal. Support makes all the difference.

With consistent encouragement and practical tools, girls can feel more confident managing their cycles and continuing to thrive in sport, not just now, but for years to come.

References 

Sport England (2018). Puberty and sport: An invisible stage. Women in Sport.