Skip to navigation
Vitamins &

What Is an Irregular Period? Identifying Different Symptoms of PCOS

PCOS Symptoms and Irregular Periods

You might be surprised to know that the average woman has around 400 periods during her lifetime. The average period according to the NHS lasts around five days,i and with the average cycle being around 28 days, however this can range from 21 - 40 days depending on hormone levels.ii

We understand that whilst these may not be the most exciting facts to have at your disposal, they are important for a lot of reasons. For instance: what if your periods don’t match up to the average? And what if you’re not having periods at all?

Experiencing irregular periods can be confusing and come with a whole host of different emotions. First things first, it is important for you to know what an irregular period is. There are several types of irregularities that may affect you. This piece will give you a breakdown of these irregularities and symptoms that come with them. Read on to find out more.

Light or infrequent periods (Oligomenorrhea)  

Don’t let the complicated spelling throw you off just yet! Oligomenorrhea is when your periods are more than 35 days apart and you’re having four to nine periods a year. This can be common if you’ve only recently started having a menstrual cycle. Some young women don’t have a regular cycle for several years when their periods start, which is considered normal and not usually a cause for concern.

If your cycle varies by a few days from one month to the next, it’s also not usually thought of as irregular. Some women have a period every three weeks, others every five – either way it’s not out of the ordinary unless you have periods that are less than three weeks or more than five weeks apart.

Frequent periods (Polymenorrhea)  

Having periods that come less than 21 days apart is known as polymenorrhea. If you have polymenorrhea your periods may also be irregular and/or unpredictable. Polymenorrhea can affect your fertility, because you ovulate sooner during your cycle than normal and often infrequently, at different times every month.

Heavy periods (menorrhagia)  

During a normal period you lose about 30ml of blood. If you have a heavy flow, you may lose more. If you bleed more than 60ml of blood it’s classed as ‘menorrhagia’ - excessive bleeding. Heavy periods are often also painful (see dysmenorrhoea, below) and can last more than seven days.

You can tell if you have heavy periods if you have to use an excessive amount of tampons or pads – or if you have to use both together. Bleeding through to your clothes or bedding is also a good indication.

According to the NHS, heavy periods doesn’t necessarily mean there’s anything seriously wrong, but it can affect you physically and emotionally and disrupt your everyday life.

Abnormally light periods (Hypomenorrhoea)  

This is the opposite of heavy periods, meaning you’ll have a very light flow and your periods may not last very long. This can be caused by taking the contraceptive pill or using another hormone-based method of contraception. However, it isn’t thought to cause fertility problems any more than having a normal cycle.

Absent periods (Amenorrhoea)  

There are two types of amenorrhoea:

  • primary amenorrhoea happens if you don’t start having periods by the age of 16;

  • while secondary amenorrhoea is when you previously had regular periods but they have stopped for at least three months.


Painful periods (Dysmenorrhoea)  

This is when you get painful and frequent cramps during your period. Primary dysmenorrhoea is caused by the uterus contracting, and is often accompanied by heavy periods. Secondary dysmenorrhea is caused by another condition such as endometriosis or uterine fibroids.iii

Physical and emotional effects of irregular periods

Period problems are very common. That being said, it doesn’t stop the physical and emotional impact they may cause. Some of the long-term effects of irregular periods are physical, such as:

  • iron deficiency anaemia (can be caused by menorrhagia)

  • osteoporosis (can be caused by amenorrhea)

  • infertility (can be caused by amenorrhoea and oligomenorrhoea).

But period problems can affect your mental wellbeing too, as some – particularly painful and heavy periods – can have a negative impact on your ability to work and your social life. lthough it can be difficult, there are various ways you can optimise your emotional health with PCOS.

Common causes of irregular periods

There are also many different things that can cause the different types of period irregularities – here are some of the most common causes:

  • Hormone imbalances (such as unbalanced oestrogen and progesterone levels)

  • Hormone treatments (including hormone-based contraception)

    • Certain medicines such as antidepressants, anti-anxiety medicines, anti-inflammatory medicines and thyroid medicines.

    • Weight loss/gain

    • Eating disorders

    • Stress

    • Over exercising

    • Uterine fibroids or polyps

    • Endometriosis

    • Thyroid problems (overactive or underactive)

    • Smoking

    • Polycystic ovary syndrome (PCOS)

According to Patient, period problems affect about 7 out of 10 women who have PCOS. With PCOS you may have consistently infrequent or light periods, or no periods at all. Some women with PCOS, however, may suffer from heavy and/or painful periods. However, if you have irregular periods it doesn’t mean you definitely have PCOS.

How does PCOS causes irregular periods?

If you have polycystic ovaries, it’s highly likely it will cause problems with ovulation. In other words your ovaries fail to release an egg each month, which means you won’t have regular periods. This happens because eggs developing in your ovaries may not mature fully enough to be released, though nobody really knows why. High levels of androgens can also disrupt your cycle, which can have an effect on ovulation, as can high levels of insulin – which is something else often found in women with PCOS.

And despite PCOS having many symptoms that can be distressing, there is evidence that having period abnormalities may affect your emotional well being more than anything else. One study – which found that women with PCOS may have significantly higher levels of psychological distress than the general population – claims that the main source of mental health problems in women with PCOS is period problems, including having an irregular cycle.iv

What can you do to treat irregular periods?

The good news is there are treatments available if you have irregular periods. Speak to a healthcare professional if you have consistent rather than occasional period problems such as heavy or painful periods, periods that last more than seven days, or infrequent or too-frequent periods.

If your period problems are caused by an underlying medical disorder – such as a thyroid disorder – treating that disorder may help get your cycle back to normal. Hormone therapy may also help control irregular periods, including the contraceptive pill and other forms of contraception that release progestogen (the synthetic form of progesterone) into the body. If you’re diagnosed with PCOS, you may also need other treatments to control any other symptoms.

Lifestyle changes

There are also some things you can do for yourself, depending on what may be causing your irregular periods. For instance if you exercise too much it can affect your cycle, so reducing how much you exercise may be helpful. Some women find they have period problems when they’re under a lot of stress – if that’s the case, learning how to manage your stress could make a big difference to your cycle.

Weight gain can also cause problems with ovulation, so if you’ve gained a lot of weight recently, shedding some of those excess pounds could see your period irregularities improve. Exercising can help you regulate your menstrual cycle as well as improve other PCOS symptoms. On the other hand if you’ve suddenly lost a lot of weight, your periods may also have become infrequent or even non existent. In this case getting your weight back to a normal and healthy level may be the only thing you have to do to see your cycle become more regular. Aim to eat a balanced diet that includes a decent amount of healthy unsaturated fats, as your body needs healthy fats to manufacture hormones.

As some medicines can cause problems with periods, it may be a good idea to have a chat with your GP if you’re taking any kind of regular medication. However, never stop taking a prescribed medicine without speaking to your doctor first.

Explore the rest of our PCOS hub to learn more about your condition and tips for managing symptoms.




  3. AAFP Clinical Evidence Handbook: Dysmenorrhoea. Available online:

  4. , et al. Differential Contributions of Polycystic Ovary Syndrome (PCOS) Manifestations to Psychological Symptoms. J Behav Health Serv Res. 42(3):383-94. doi: 10.1007/s11414-013-9382-7. Available online:


Related Posts?


Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Olivia Salter


Olivia Salter has always been an avid health nut. After graduating from the University of Bristol, she began working for a nutritional consultancy where she discovered her passion for all things wellness-related. There, she executed much of the company’s content marketing strategy and found her niche in health writing, publishing articles in Women’s Health, Mind Body Green, Thrive and Psychologies.

View More