When will my teen's next period be?

Predicting your teen's next menstruation

Quick summary 📝

1️⃣ Irregular periods are normal at first – it can take up to two years for cycles to settle, so predicting the exact timing isn’t always possible

2️⃣ Tracking symptoms like fatigue, acne, or mood swings can help teens spot signs their period is coming, even if their cycle isn’t regular yet

3️⃣ Providing reassurance, period products, and a tracker like luna can help your teen feel more confident and prepared for the unpredictability of their cycle

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There’s often a lot of emphasis on preparing for a first period, but we hear less about what happens afterward, as teens begin to settle into their menstrual cycles.

As a result, many teens ask us through our app, luna, about when their next period will arrive – confused about how to find out, and what to do to manage it.

So, if your teen is coming to you with the same question, we want to offer some clarity to help you support them.

The reality is, periods can be irregular at the start

The truth is, it’s impossible to predict exactly when your teen’s next period will arrive, especially in the first couple of years after their cycle starts.

It’s completely normal for periods to be irregular at this stage as the body adjusts to hormonal changes.

Some cycles may be shorter, others longer, and occasionally they may skip a cycle altogether.

While it can be frustrating for your teen to deal with this unpredictability, reassurance goes a long way – let them know that irregular periods are part of the settling-in process and typically become more regular over time (usually within the first two years).

Preparing for irregular periods

So, how can a teen prepare for the unexpected? How can they feel more secure with the possibility they'll get a period when they don't expect it?

Firstly, encouraging your teen to track their periods can still be helpful, even if their cycle isn’t regular yet – luna’s period tracker allows them to log their periods but also their moods, skin, pain and sleep which can also help them identify signs their period is on the way.

And in time, the tracker will offer a more accurate estimate of when their next period might occur based on their average cycle – these predictions become more accurate as periods become more regular.

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As for preparing for unexpected periods, it’s a good idea for your teen to carry a period kit with period products like pads, tampons, or period underwear.

Wearing a panty liner in the days leading up to a possible period (at the start they can estimate 28 days after their first period) can provide added peace of mind. Panty liners are lightweight and can catch very light flows. Just remind your teen to change the liner every 4–6 hours for comfort and hygiene.

Signs a period might be coming

Even when a teen's cycle is irregular, they may notice some common signs that their period is on its way which can be very helpful.

These symptoms can appear in the days or week leading up to their period:

• Fatigue: feeling more tired than usual
• Acne: breakouts or oilier skin than usual
• Mood swings: feeling more sensitive or emotionally charged
• Bloating: a slightly rounder stomach or reduced appetite due to bloating
• Cravings: a stronger appetite or sudden desire for specific foods like chocolate
• Breast pain: tender or swollen breasts

Helping your teen recognise these signs (and encouraging them to track them in the luna app) can make them feel more prepared and in control.

How you can support your teen

New periods can be a challenging and frustrating experience for lots of teens, so your support and reassurance can make all the difference. Encourage your teen to track their period and watch for these common signs, as this can help them feel more confident and less anxious about the unpredictability of their cycle, and over time they'll find it becomes much easier to predict and manage their periods.