Help! Irregular Periods And Unusual Menstrual Bleeding in Teens Explained

Especially for teens, irregular periods can be a normal thing that comes with puberty. But there are many other reasons why they could be experiencing irregular bleeding. Read on to learn what to look out for. 

For a teen, getting your period is already irritating enough, so getting your period at times you don’t expect it – or not at all – is a serious ugh. But don't worry — it’s probably nothing serious.

Especially for teens, irregular periods can be a normal thing that comes with puberty. Their body is still adjusting to its menstrual cycle, and you may find that their periods settle down with time.

Having said that, there are some reasons why teens might be getting irregular periods — including their biology, stress levels, and the type of birth control they may be taking.

Here are all the reasons why your child could be experiencing irregular periods or have unexpected mid-month flow.

Two main causes of irregular periods in women & teens

There are two types of irregular bleeding, the first being breakthrough bleeding. This happens when your teen experiences period blood and menstruation when they don’t expect it, for instance in between their normal cycles.

On the other end of the scale, is when your teen stops having periods altogether, or they become less frequent and don’t conform to a “usual” monthly cycle. They may find they get periods every three months, or even less frequently.

Causes of breakthrough bleeding

Birth control

If your teen has just started birth control or switched to a different type of contraceptive pill, their hormones will be out of sorts. Birth control is designed to change the usual hormonal cycle, and this can cause bleeding between cycles. But don’t worry – this should even out on its own after a few months. If it doesn’t, talk to their doctor about trying a different brand of birth control or another alternative.


Endometriosis is a painful condition causing the lining of the uterus to grow outside the uterus. Yes, it’s as unpleasant as it sounds. It’s been estimated about 6-10% of women have endometriosis, with it being most common in women ages 30-40. On top of the pain, this condition can cause spotting between regular cycles. Treatment for endometriosis depends on the severity of the condition. In mild cases, it can be treated with painkillers. If it worsens, your doctor may put your teen on birth control to treat the symptoms and in some cases, surgery can be performed to remove the tissue growing outside the uterus.

Polycystic ovary syndrome (PCOS)

PCOS is a condition caused by the imbalance of androgens (male sex hormones) which leads to the growth of small cysts inside the ovaries. As a result, women with PCOS don’t ovulate regularly, causing bleeding at unexpected times. PCOS can be treated by improvements to eating habits or exercise regimen, or by taking birth control to regulate the cycle.


The thyroid is a butterfly shaped gland located in your neck. Your thyroid gland is responsible for regulating your metabolism and releases important hormones into your body. If a thyroid gland is overactive or under-active, irregular bleeding can occur. Some additional symptoms can include excessive sweating, sensitivity to cold and a rapid heartbeat. If you suspect your teen has an issue with their thyroid gland, their doctor can test its functionality by performing a blood test and will prescribe medication accordingly, depending on the results.

Your cervix

The blood shed from your uterus during the menstrual cycle is released in the same place blood from the cervix would flow – your vagina. The difference is the uterus shedding is normal and expected while blood from the cervix is an indicator of an underlying issue. There can be various causes for cervical bleeding, with the scariest being cervical cancer. (Other causes include STIs like chlamydia).  

Before you freak out, cervical cancer is extremely rare and both cervical cancer and chlamydia are treatable once diagnosed.

The important lesson to take from this is your teen should be making regular visits to a gynecologistwho will catch this sort of issue and treat it. If your teen has never been to a gynecologist, speak to your family doctor and they will be able to refer you to someone.

Disruption to your teen's monthly cycle: missing periods

In addition to breakthrough bleeding, no bleeding is considered a form of irregular bleeding. This applies to adults who have never gotten their period or people whose monthly cycles have abruptly stopped happening. Missing a period can be scary, but it doesn’t necessarily mean that your teen is pregnant. Other than pregnancy, there are a variety of reasons this could be happening, including:

Too much exercise

Being active is great and has so many positive benefits for your mind and body. However, if your teen is pushing themselves too hard it can have a negative effect on their body and overall health. If they're going too hard at the gym and pushing their body further than it wants to go or not nourishing themselves properly, the body won’t be able to produce enough estrogen to complete its menstrual cycle. If this happens at least three months in a row it becomes categorized as a condition known as amenorrhea, which is prominent among gymnasts, dancers and other professional athletes.

Their weight

A healthy body weight is directly related to a regularly occurring cycle. If your teen is slightly underweight or overweight, it can affect the gland in the brain responsible for regulating some of the body’s usual processes, like producing estrogen. Additionally, a major drop in weight or a low-caloric diet can prevent the body from producing estrogen and in turn deter their period from coming to town. Here are some of the best foods they can eat during their period.


Mental health is just as important as physical health! Any form of stress can cause a condition known as hypothalamic amenorrhea, which happens when the area of your brain where hormones for the period are regulated stops functioning properly. Whether it’s a breakup, a bad mood or a pile up of work at school, the stress teens carry can affect their period.


When you’re sick, your body goes into fight or flight mode, meaning every inch of your body becomes focused on getting rid of the unwanted infection. Sometimes the body can be so focused on its intruder that it sacrifices other bodily functions, like the period. So, if your teen has a cold or the flu don’t be alarmed if their period decides to skip out for that month.

Birth control

There’s tons of different kinds of birth control out there, including pills that give someone a period once every three months or once a year. With birth control, it’s also possible to skip a period if you continue to take the hormone pills. As mentioned, many doctors put patients with endometriosis on birth control to prevent their period from coming because having your period can make symptoms worse if you suffer from endometriosis. If you’re considering birth control for your teen to skip a period, ensure you speak with a physician. 

Irregular period FAQs

Are irregular periods dangerous? Are irregular periods more common in teens?

Not necessarily! They definitely are more common amongst teenagers as their cycle regulates, so don’t freak out. It’s just good to rule everything out and ensure that nothing else is going on, especially if they have other symptoms like bloating, swelling, or pain.

Is missing periods normal?

Sometimes, yes. There are a variety of reasons why the body could skip out on periods, so it’s important to have a look at your teen's overall health and speak to a professional if you are concerned.

Why would my teen miss a period?

It could be stress, hormonal changes, or the birth control they use. In order to find a solution to irregular periods, you may need to talk to a professional who can get to the bottom of things for you.

How long do irregular periods last?

That depends on why your teen is getting them. If it’s just stress making them miss a period, they could just miss out on them for that one month, whereas breakthrough bleeding and spotting can go on for longer.

Are irregular periods something that come with birth control?

Not necessarily, but they are linked. The use of birth control can make the body react in this way, so if they're experiencing irregular bleeding and they've just started the pill or have recently switched to a new one, they might have to change their contraception.

Are there any home remedies we should try?

Make sure your teen is taking care of themself, like eating well and getting the right amount of exercise.

Are irregular periods something to do with ovulation and fertility?

Not always. As well as genetics, lifestyle and diet have a role to play in an individual's menstrual cycle.

Your teen's body is their temple and it’s important to take care of it, so it functions at its best. If your teen is experiencing irregular periods, don’t panic. As you can see, there are many reasons this could be happening and it’s important to know that in many cases an irregular period is normal. If you’re concerned about your child's symptoms or you believe their symptoms correlate with some of the conditions talked about in this post, get in contact with their doctor or have them start seeing a gynecologist regularly.  

Our period panties are a great option to stay leak-free no matter when your teen's period decides to show up. 

To download in Canada, please click here.

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