Periods can be a bit of a mare. They’re messy, a faff and tampons are expensive. Premenstrual syndrome (PMS) can also cause cramps, pain or us too feel moody or irritable.

Periods however are crucially important for women. Not only do they allow us to reproduce (if we so wish), the complexity of different hormones involved impact on a range of different internal physiological processes which help to maintain homeostasis from stimulating the maturation of our sex organs to preserving bone density.

If you aren’t getting a period, it’s a sign your body’s reproductive system isn’t working properly, and while this may have some perceived benefits, you could really be putting yourself at risk.

There are links between lack of a period and:

  • Brittle bones – osteopenia and osteoporosis
  • Cardiac issues
  • Neurodegenerative diseases (Alzheimer’s and dementia)

Periods can stop for a variety of reasons and is commonly referred to as amenorrhoea.

Primary Amenorrhoea is the absence of a period before 16.

Secondary Amenorrhoea is the cessation of normal periods, usually for over 3 months in a previously menstruating woman.

Polycystic ovary syndrome (PCOS) is also a form of secondary amenorrhoea believed to affect 12-18% of women (Azziz et al, 2004). It is different from polycystic ovaries in so much as the latter refers to the presence of many cysts within the ovaries whereas the former, a syndrome is the presence of a group of symptoms associated with small follicles on the ovaries. These follicles are usually identified by an ultrasound. Common symptoms include irregular or no periods, excess androgens (testosterone and another hormone called DHEA) and insulin resistance.

Pregnancy! An easy one to rule out with a test.

Menopause or Pre-menopause – Most women undergo the menopause at around 50 years when their reproductive system stops.

The first port of call should always be your GP or health care provider. They will be able to conduct a thorough assessment to inform the correct diagnosis and treatment plan.


So, with that background in mind let’s discuss what exactly is meant by hypothalamic amenorrhoea (HA)?

In HA, amenorrhoea is caused by the inability hypothalamus to maintain balance in terms of signalling. This can be in both primary and secondary amenorrhoea.

The hypothalamus is the control centre of the brain and master endocrine gland. The Endocrine system refers essentially to the system responsible for your hormones. The hypothalamus releases hormones which in turn cause the release of hormones from the pituitary gland which then travel to target tissues.

There are two lobes of the pituitary gland, the anterior and the posterior which are each responsible for different hormones. For the purpose of this article, we are only going to focus on hormones released from the anterior pituitary gland.

Just in case you need a reminder hormone are chemical messages released from glands which travel to specific target tissues where they have different effects.


The image above shows how the hypothalamus stimulates the release of different releasing hormones which in turn stimulate the anterior pituitary to release further hormones which go off to target tissues. Again, for the purpose of explaining hypothalamic amenorrhoea I want you to look at:

Thyroid Releasing Hormone (TRH) which goes on to stimulate the anterior pituitary gland to produce Thyroid stimulating hormone (TSH) which travels to the thyroid gland.

Corticotropin Releasing Hormone (CRH) which goes on to stimulate the anterior pituitary gland to produce Adrenocorticotropic hormone (ACTH) which travels to the adrenal cortex.

GonadotropinReleasing hormone (GnRH) which goes on to stimulate the anterior pituitary gland to produce FSH and LH which travel to the ovaries and testes.



I hope I haven’t lost anyone so far but now let’s get into the nitty gritty.


So, what can cause the hypothalamus to lose control of signalling?

As it turns out some pretty basic everyday things:

  • Food, or lack of
  • Exercise
  • Stress
  • Sleep

Let’s go through in turn and see how each of the above can impact on our hormones in turn switching off our periods.



Looking at the HPA axis above we can see that the hypothalamus controls your reproductive cycle and your metabolism.

If you’re not eating enough, your brain (hypothalamus) is going to know about it, and its response is to slow down efficiency or switch things off.

You have two autonomic nervous systems. Your sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS). You can think about the SNS as your “fight or flight” and your PSNS as “rest and digest” or “feed and breed”. I’ve summarised the difference below.


Basically, you have to think of you SNS as running from a Tiger, when your body needs purely to survive or run it starts switching off systems that aren’t totally essential, basically you can’t give birth whilst running from a Tiger.

However, in our modern day our body doesn’t know the difference between running from the tiger and running at Barry’s Boot camp or simply having to survive the day without adequate calories. One’s metabolism slows to make the fuel last longer, CRH and ACTH rise, yup you need cortisol to maintain your energy levels if you don’t have actual food to do this, and GRH is blocked so you don’t make FSH or LH to maintain a menstrual cycle.

Increased caloric intake and subsequent BMI has been found to lead to a return of the menstrual cycle in numerous studies. One study found that for every single unit increase in BMI, a woman had a 34% increased chance of their period returning (Falsetti et al, 2012).

Putting calories back in may not be easy for everyone. We live in a world which values slenderness and initially eating more can feel uncomfortable. It may be that you want to call in some help from a registered nutritionist or dietitian, or even a psychologist who may be able to support you best with changing attitudes towards food and body image.

Upping food intake to support your body won’t just see the return of your period. You’ll also likely have better energy levels, sleep, feel warmer, have less brittle and dry skin and bones. As you start nourishing your body again your metabolism will speed up. Remember TRH and TSH which goes on to covert T4 into active T3 responsible for your metabolic functioning. Our bodies are smart so again with extra food our resting metabolic rate increases, we might sleep at a higher temperature or subconsciously just move a little more in the day. Personally, a smart, happy and optimally functioning body is the best way forward.



There’s no getting round the extensive benefits of exercise for mental and physical health. I actually prefer to it joyful movement as exercise implies you have to be in lycra or in the gym for it to count. Actually, joyful movement might be a dance class, walking to work or a bit of house work when you can play good tunes.

I was also reluctant to say excessive exercise may cause HA because the truth is our bodies are all unique in how much exercise we can handle. For some individuals, several hard-core fitness classes a week could be enough to dysregulate the hypothalamus. In fact, multiple studies have shown that 48 to 79% of women who exercised 3 times per week or more had disordered menstrual cycles. These women were of a stable weight but their food intake was not monitored so it’s possible they were not eating optimal caloric intake (De Souza et al, 2003).

Exercise can be a form of stress relief, but it’s also a form of “stress” to the body. A little stress, known as eustress or hometic stress can be good, but too much and we start seeing a rise in cortisol via CRH and ACTH. Both cortisol and sex hormones are made from cholesterol, so when the body is stressed there is what’s called the “pregnenolone or cortisol steal” which shuts off the other pathway preventing the production of oestrogen and causing amenorrhoea.


We also live in a culture that places a huge amount of value on a lean tones aesthetic with visible muscle and little body fat. “Lean” is a buzzword and many aspire for it, however one can be too lean and actually we need some body fat which has numerous benefits to the body – protection of key organs, warmth, and to produce certain hormones including leptin and oestrogen. The combination of lack of caloric intake and over exercising can result in too little body fat and therefore inadequate oestrogen production again resulting in amenorrhoea.



I briefly touched on the difference between eustress and “stress” stress. The former is the kind of stress that can be beneficial and make us stronger. The latter is what can trigger excessive cortisol release and may result in that “pregnenolone or cortisol steal” which shuts of the other pathway preventing the production of oestrogen and causing amenorrhoea.

Under eating and over doing exercise are two stressors but so are other everyday things, putting too much pressure on ourselves, feeling like we lack control etc.

It is important to note that individuals may not even be aware of the stress they’re under or feel excessively stressed, but there are lots of mental and physical stressors at play that may be having an impact on the body even things like pollution and long working hours we don’t notice or just take as a given which maybe having an impact on the body.



Sleep is like the bit, but also the thing you may want to tackle first. 7-9 hours was the ideal amount of sleep for adults as concluded by the US National Sleep Foundation, with between 8-10 for teenagers (Devlin, 2018). However, in the UK the average in 6.8 (Devlin, 2018)

Lack of sleep is a significant stressor on the body and again results in that “pregnenolone or cortisol steal” and may risk amenorrhoea. Research also supports that sleep is impaired in underweight individuals.



A word on oral contraceptive pills (OCPs)

Many women who go to the GP with amenorrhoea will be offered the OCP. This is usually a low dose of oestrogen, progesterone or a combination of the two. Whilst this will have some protective effects for bones and in cases is necessarily, it doesn’t address the underlying cause of amenorrhoea and continuing to follow a “lifestyle” that cannot support normal reproductive function is not necessarily healthy. I’m not saying the OCP is “bad” as such but if you are using it without making necessary changes to support your long term wellbeing it may be worth speaking with your health care provider.

Further, many women who are on the OCP and not getting adequate calorie intake to support their needs or whom engage in over exercising may also be unaware they have amenorrhoea because the OCP regulated the menstrual cycle and usually results in an artificial bleed. In such cases amenorrhoea may go unnoticed so it may be important to really evaluate whether you are adequately fuelling your body or taking enough rest days, getting enough sleep and managing stress etc.



Hypothalamic amenorrhoea is increasingly common in women. We live in a world where excessive exercise and “healthy” eating is glamourised and where stress and lack of sleep are all too common place. Addressing these things can help the hypothalamus maintain balance and allow our reproductive system and overall body to function as it should.

If you are experiencing amenorrhoea please do visit your GP and speak to them about ways you can get adequate support.



I highly recommend the book “No Period Now What? A Guide to regaining your cycles and improving your fertility”. As a place to start.

There is also a facebook group for support you can find here.

Link to the impacts of being underweight here.

Azziz, R., Woods, K., Reyna, R., Key, T., Knochenhauer, E. and Yildiz, B. (2004). The Prevalence and Features of the Polycystic Ovary Syndrome in an Unselected Population. The Journal of Clinical Endocrinology & Metabolism, 89(6), pp.2745-2749.

Falsetti, L., Gambera, A., Barbetti, L. and Specchia, C. (2002). Long-Term Follow-Up of Functional Hypothalamic Amenorrhea and Prognostic Factors. The Journal of Clinical Endocrinology & Metabolism, 87(2), pp.500-505.

Rinaldi, N., Buckler, S., Waddell, L. and Blondin, M. (2016). No period. Now what?. Antica Press.

De Souza, M., Van Heest, J., Demers, L. and Lasley, B. (2003). Luteal Phase Deficiency in Recreational Runners: Evidence for a Hypometabolic State. The Journal of Clinical Endocrinology & Metabolism, 88(1), pp.337-346.

Devlin, H. (2018). Sleep: how much do we really need?. [online] the Guardian. Available at: [Accessed 16 Dec. 2018].

Fairburn,C.G (2008) Cognitive Behaviour Therapy and Eating Disorders. Guilford Press: New York.


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