In the first years of getting their period, tweens and teens will often experience irregular cycles.
They may get their first period and not see their next period for several months. They may have long gaps between periods, with longer cycles being more common than shorter cycles. Not knowing when their period is going to arrive can cause worry and anxiety, especially dealing with a surprise period during school hours. In this article we will explain the science behind irregular periods during the puberty years and explain how you can help your tween or teen know when their next period will likely arrive.
Periods during the puberty years often go missing
A growing tween or teen starts creating the hormones needed for the menstrual cycle, but the reproductive system is still in maturation mode, along with the rest of the body, for some years. A maturing reproductive system is still working on setting up the brain to ovaries connection that makes menstrual cycles more regular. Irregular periods during puberty are a short-term experience and, if all else is healthy and good, menstrual cycles will regulate as the years go on.
This means most tweens and teens experience irregular cycles, longer cycles, and missing periods. Often an irregular cycle is nothing to worry about at this stage.
When puberty bodies are busy, periods may come late
In order to get a period, we need to ovulate. During tween and teen years, the majority of the body’s energy is going towards development and growth. It’s a busy time for the body, and ovulation is often last in line of the priorities. If we don’t ovulate, we don’t menstruate. No ovulation is the primary driver behind longer, irregular cycles.
Real, physiological menstruation is considered the bleed that happens about two weeks after ovulation, when the hormone progesterone drops.
As adults, we may skip ovulation for similar reasons when we’re sick or stressed and our body’s resources are moved elsewhere. But as teens this is a constant state during puberty, and ovulation will happen only when the resources are made available. If a teen goes through a big growth spurts and gets much taller quickly, they will often not ovulate, and therefore not menstruate, during that time.
A regular cycle is considered to mean periods that happen every 21-35 days. Most of us experience some irregularity within those parameters until menopause (around 10% of all cycles are irregular).
The different kinds of periods your teen will experience
As mentioned, ovulation is needed for your teen to experience real, physiological menstruation. However, we all know that if we experience a few days of bleeding around the time we expect to see menstruation we still view this as “a period.” So, what’s happening?
When we don’t ovulate, this is called an anovulatory cycle. As explained, anovulatory cycles are most common in those puberty years. And, importantly, an anovulatory cycle can include bleeding - light, pink-ish spotting is possible - but this is a breakthrough bleed caused by hormonal shifts, and not real or physiological menstruation.
A cycle has no ovulation and ends in a breakthrough bleed may look and feel a lot like a cycle with ovulation that ends in menstruation, especially to a tween or teen just starting out experiencing periods and getting used to what is normal for them.
Tracking other signs of ovulation like cervical fluid, ovulation cramps, and basal body temperature can help a teen figure out if they are having an anovulatory cycle. But for many, this is not necessary information, and will happen a lot.
“Help! My kid got their first period, but now it’s been three months and no period!”
This is a common experience. The tween or teen will have their first period and then the next period…just doesn’t happen. They may have three months or even six months before the next period arrives.
If this happens with your tween or teen, you may feel a sense of relief. Ah, no periods again! This is a good time to help your child understand and prepare for what’s happening with their body during the puberty years, if you haven’t already. Build a period kit together they can carry to school or sleepovers. Do some period care shopping for tampons, pads, period panties, or a menstrual cup and learn how to use them.
As your child gets older, regular periods will become a sign of their good health and wellness. The American Committee for Obstetricians and Gynaecologists advises that the menstrual cycle be viewed as a fifth vital sign for teens by healthcare providers. ACOG encourages tracking cycles for the puberty years, and beyond.
You can expect irregular cycles from the first period for four years or so. After that time, periods should become more regular and fall within the 21-35 day window.
Causes of irregular cycles in older teens
As teens get older, their reproductive systems reach maturity and growth spurts slow, meaning their menstrual cycles should become more regular. If this does not happen around four years into their menstrual cycle experience (so four years since their first period), it’s a good idea to be mindful of what other issues could be causing their long cycles and missing periods.
Common causes of irregular cycles in older teens are undereating and over-exercising. The body needs good nutrition to have the energy to ovulate, and then menstruate. Teens who are skipping meals, crash dieting, following strict diets, or teens who have eating disorders, may find they stop experiencing menstrual cycles as a result.
Over-exercising may happen in teens who are deeply involved in sports, training for an event, competing in sports, or working for a scholarship. This can also be seen in teens who are crash or strict dieting or those who develop eating disorders.
Another issue that causes ovulation to stop, and periods to stop, is chronic stress. If a teen is experiencing a lot of stress in their life, from home or school sources, they may find that their periods become irregular. Stress can come from college applications, bullying, romantic relationships, or friendship conflict.
The menstrual cycle is an amazing real-time feedback system and adjustments in a teen’s diet or exercising routine can be reflected pretty quickly (one to three months) in more regular menstruation. Obviously, if there is a more serious issue (like an eating disorder) at play, consult your healthcare practitioner.
How to track irregular cycles and predict the next period for teens
Although menstruation is irregular during the puberty years, there are ways to track irregular cycles and learn when to expect the next period. You don’t have to stay completely in the dark, and your tween or teen doesn’t have to be anxious, waiting for the next period with no clues at all as to when it might happen.
As mentioned above, ovulation necessarily precedes menstruation. If you can track ovulation and know when it happens, then a period will predictably arrive within 12-14 days.
The most accurate way to track when ovulation has happened is basal body temperature. Basal body temperature is your temperature under your tongue first thing in the morning. It’s also sometimes called resting temperature. The body gets slightly hotter after ovulation and this can be picked up if basal body temperature is taken most days. Once ovulation is confirmed from the temperature shift, then the countdown to the next period begins. This makes preparation much easier!
You can also use accurate cycle data like this - data that shows when and if ovulation is happening - to work with your doctor if menstrual cycles stay irregular into later teen years.
Check out Teena: a period tracking device that uses basal body temperature to predict your next period. No more worries, no more surprises. Just accurate period tracking data so you can be prepared.
