Put simply, hypothalamic amenorrhea (HA) is the absence of a menstrual cycle in women of reproductive age. Most commonly – accounting for around 30% of cases – HA is caused by significant sudden weight loss, stress, undereating or over-exercising, or a combination of these.   


There are, however, a few different forms of HA. The first being primary HA. Primary HA is the absence of menarche altogether, which should be investigated professionally if a period still hasn’t occurred 3 years after puberty begins. Secondary HA is defined when formerly regular cycles have ceased for 3 months or for 6 months in those that experience more irregular cycles. Secondary HA is usually found in those such as athletes who have lower body fat percentages and higher energy outputs. It is also often referred to as functional HA.


Having a regular and healthy period isn’t just important for those women who hope to start a family. Our menstrual cycles are an indicator of female health, and do so much for our health at the same time. So, what is actually happening in the body that makes our period go MIA?


What is Happening?


During times of high stress, undernourishing our bodies and over doing it on the exercise front this can put our bodies into fight or flight mode. Meaning a message is sent throughout the body that this is not the time for reproduction due to suboptimal conditions. Basic bodily functions like respiration and circulation are prioritised, and functions like ovulation are switched off leading to a missing period.


Governing all of this is our brain and most importantly the hypothalamic-pituitary-ovarian (HPO) axis, which is responsible for reproductive hormone secretion. Normally the hypothalamus secretes gonadotrophin-releasing hormone (GnRH) which stimulates the pituitary gland to release luteinising hormone (LH) and follicle-stimulating hormone (FSH). The latter 2 are important for maintaining our follicular phase into healthy ovulation within the ovaries which in turn keeps oestrogen levels sufficient. As you can see it has a bit of a domino effect. If one is insufficiently secreted or there are insufficient levels then the next becomes compromised. 


This fight or flight response is a normal response to stressful situations that is an evolved mechanism within humans, developed to conserve our energy stores when we need them most. In order to send our bodies into the opposite state, our rest and digest response, we need to help it feel safe through reducing our stress - whichever way that may be showing up for you; not eating enough, overexercising, high work/study load etc.


Long-term Health Effects


Again, female menstrual cycles are an indicator of health. Without one a lot of other factors are impacted. A large concern is with the oestrogen deficiencies seen in HA patients, as oestrogen plays a role in many aspects of female health. Not just our hormone health.


Cardiovascular effects: Within the blood vessels oestrogen helps dilate and relax the vessels, and also protects against damage such as atherosclerosis. This is evident in women experiencing menopause where accelerated atherosclerosis and CVD risk is increased due to the drop in oestrogen levels.


Bone effects: Oestrogen is imperative for bone metabolism; it stimulates bone-building activity. Therefore, it’s no wonder that those suffering from HA lose bone mineral density (BMD). When oestrogen is absent or insufficient bone starts to deteriorate due to the absence of oestrogen promoting bone-resorption activity. This puts those at risk of developing osteoporosis or osteopenia.


Psychological effects: Although the aspect of stress can actually be a cause of HA, HA also brings other psychological impacts. Compared to regularly menstruating women, studies have shown that those with HA have higher rates of anxiety and depression, alongside heightened difficulty coping with day-to-day stress.


Impacts on Fertility: Unfortunately, due to the stigma around periods being bothersome for a lot of women, when a period goes MIA it is often overlooked and seen as a good thing being one less thing to worry about. However, when it comes time to attempt pregnancy this is when women become aware of the necessity of ovulation and a monthly period. Without ovulation an egg isn’t released and awaiting fertilisation. And apart from the actual period, ovulation is the main event! It is the fertile window within a monthly cycle.


Steps to Resolve HA


Luckily once diagnosed with HA it is generally reversible. But before we go on to list the factors that can help HA, it is important to reiterate that you should talk to a health professional about a HA diagnosis before self-prescribing techniques, to be sure other factors that could be causing your missing period are ruled out first.


Lifestyle: For many women with HA, it is common that a ‘more is better’ lifestyle is taken when in hindsight taking a ‘less is more’ approach is often what they need. For example, when the factor of over-exercising is causing HA we must pull it back to allow the body more time to rest and feel safe in order to ovulate. Most studies show that when exercise duration and intensity is reduced menses commonly resume within a year.


Dietary: Disordered eating and under-eating are both common symptoms of HA. The former is usually very restrictive of certain food groups and the latter is basically a lack of calories or energy. Both cause severe undernourishment, and weight loss along with it, that triggers the fight or flight response. For our bodies to prioritise ovulation we need to be giving it all the nourishment it needs to regulate hormone levels and release a healthy egg. The key is to have sufficient energy availability for your body to perform basic functions and cover extra energy outputs, but also ensure proper micro- and macronutrient intakes are met.


Psychological: Sometimes stress is inevitable but managing your stress during HA recovery is paramount for ovulation. For our body to return into a balanced state, and not remain in fight or flight mode, lean into things that create more calming effects for you; reading a novel, taking a bath, yoga sequences, cooking a nourishing meal or going for a slow stroll are all fabulous options. But finding what works for you is important. And it may be good to note here that exercise is also a form of stress, so maybe don’t lean into that run just now.


To bring female bodies more cycle nourishing nutrients, Active Collagen has formulated a hot chocolate powder that is full of period loving goodness – Active Cycle. Visit our online shop here to get your hands on some and start giving your body an extra nutrient boost. 


Klein, D. A., Paradise, S. L., & Reeder, R. M. (2019). Amenorrhea: A Systematic Approach to Diagnosis and Management. American family physician100(1), 39–48.


Roberts, R. E., Farahani, L., Webber, L., & Jayasena, C. (2020). Current understanding of hypothalamic amenorrhoea. Therapeutic advances in endocrinology and metabolism11, 2042018820945854. https://doi.org/10.1177/2042018820945854


Shufelt, C. L., Torbati, T., & Dutra, E. (2017). Hypothalamic Amenorrhea and the Long-Term Health Consequences. Seminars in reproductive medicine35(3), 256–262. https://doi.org/10.1055/s-0037-1603581


Sophie Gibson, M. E., Fleming, N., Zuijdwijk, C., & Dumont, T. (2020). Where Have the Periods Gone? The Evaluation and Management of Functional Hypothalamic Amenorrhea. Journal of clinical research in pediatric endocrinology12(Suppl 1), 18–27. https://doi.org/10.4274/jcrpe.galenos.2019.2019.S0178


Ryterska, K., Kordek, A., & Załęska, P. (2021). Has Menstruation Disappeared? Functional Hypothalamic Amenorrhea-What Is This Story about?. Nutrients13(8), 2827. https://doi.org/10.3390/nu13082827


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