A guest blog for Menstrual Matters by Dr Julia Haarhuis, a nutritian scientist specialising in menstrual health & HA Recovery

Healthy food but are you eating enough? An egg salad. Pexels: Andy Kuzma.

When “healthy” turns harmful…

You eat organic food, exercise regularly, and maybe even lose a few pounds. Sounds like a healthy lifestyle… Right?

But then something unexpected happens: your period stops.

It’s easy to shrug it off: “my body is just getting used to the new diet,” or “I’m training hard, so it’s normal.” Yet for some people, absent periods may be a warning sign of a health condition called functional hypothalamic amenorrhea (HA). HA is a reversible disruption of the reproductive system triggered by lifestyle- and stress-related factors (1–3).

Because the female reproductive system is closely linked to your overall energy balance and perceived stress, not having periods can be your body’s way of showing it’s under too much strain.

What is hypothalamic amenorrhea (HA)?

HA is defined as the absence of periods for more than three months, or menstrual cycles that are consistently longer than 45 days, in someone of reproductive age (4) after ruling out pregnancy and other medical causes, such as polycystic ovary syndrome (PCOS), premature ovarian insufficiency (POI), or anorexia (3–5).

Has it been a while since your last period? Clean underwear on a washing line. Image source: www.kaboompics.com

In HA, the hypothalamus (the part of the brain that helps regulate hormones) reduces the signals that normally support ovulation (3, 5). This can happen because of low energy availability, mental stress, high training loads, or a combination of these factors  (2, 6).

Although HA is more common in people with significant weight loss or conditions such as anorexia, it can occur at any body size. HA is typically caused by a combination of lifestyle- and stress-related factors (1–3), not body weight alone. It is also important to note that some individuals may have underlying physiological or genetic factors that affect this hormone pathway (5, 7, 8).

Absent periods can, therefore, signal a lack of ovulation due to stress in the body. Without regular ovulation, oestrogen levels may drop, which can have long-term health impacts, such as infertility (2, 9), bone density loss and early-onset osteoporosis (9), increased risk of heart disease (9), and anxiety and depression (9). If your periods have stopped due to causes other than pregnancy or medication, you should look into it.

What happens in HA?

• In a healthy cycle, the hypothalamus releases gonadotropin-releasing hormone (GnRH) in pulses (Figure 1). These pulses signal the pituitary gland to release luteinising hormone (LH) and follicle-stimulating hormone (FSH), which then stimulate the ovaries to produce oestrogen and progesterone and allow ovulation to occur (3, 5).
• In HA, the hypothalamus reduces the frequency of these signals when it senses that the body is under strain, from not taking in enough energy (from the diet), high levels of emotional stress, or metabolic stress such as insufficient recovery from exercise (2, 5, 6).
• As a result, levels of LH and FSH fall, ovarian hormones like oestrogen and progesterone drop, and ovulation becomes infrequent or stops altogether. As a result, periods then become very delayed or stop entirely (2, 3).

For some people, these changes are associated with well-intentioned behaviours, such as increasing exercise or eating healthier meals, but this can create an energy deficit. When the brain perceives that energy is limited, it prioritises essential body functions and temporarily reduces reproductive activity to conserve resources (1,10).

Figure 1. The hypothalamic-pituitary-ovarian (HPO) axis during hypothalamic amenorrhea (HA). Stress and low energy availability can reduce the signals from the brain that stimulate the ovaries, leading to fewer reproductive hormones – this prevents regular ovulation, which ultimately results in absent periods. Created in Biorender (https://www.biorender.com/).

Why is HA often missed or left untreated by healthcare providers?

HA often slips under the radar. People with HA typically appear “healthy” – lean, active, and disciplined with food and exercise. Also, menstrual physiology beyond its basic ‘hormonal coordination’ is often absent from clinical training (15). So, once pregnancy and other health conditions have been ruled out, missing periods can sometimes be dismissed as unimportant or a medical mystery. Both patients and clinicians may underestimate the seriousness of HA.

If using hormonal contraception, you may not even realise you have HA or other conditions such as PCOS (4). Because HA is not obvious while using hormonal contraceptive medications, people may only discover that they are not able to ovulate or have regular periods once they have stopped taking them (14), for instance when they start trying to conceive.

HA and misdiagnosis

Even when they seek medical help, patients may face misdiagnosis. Since HA is a diagnosis of exclusion, other causes like PCOS or POI must be ruled out first. HA can be confused with PCOS due to overlapping symptoms, such as anovulation and polycystic ovaries (11). This matters because the two conditions require different lifestyle approaches: HA recovery depends on greater energy intake and rest, whereas PCOS is improved by reducing energy intake and increasing exercise.

Sometimes, when people report missing periods, they are offered hormonal contraception without any diagnosis being made. This will improve oestrogen levels, prevent the harmful effects of HA, and create a regular withdrawal bleed (like a period), but it doesn’t identify the underlying reason for the disruption to the natural menstrual cycle. As a result, people may continue harmful lifestyle and dietary habits.

Unsure if you have HA, PCOS, or POI? You can use this HA Reference Guide to compare your blood work: https://recover-ha.com/free-guide

Figure 2. Table comparing blood work to distinguish HA, PCOS, and POI. Snapshot from the HA Reference Guide, with permission from Recover HA.

Good News- HA is entirely reversible, even without medication…

Fueling the body. Pexels: Adrienn

Luckily, HA is reversible, no medication needed. HA is fundamentally about the brain sensing a lack of energy, insufficient for reproduction. Thus, HA recovery focuses on restoring the energy balance and giving the body enough energy to feel safe to ovulate again.

Reversing HA requires a combination of strategies:

• Increasing total energy intake and ensuring intake of micronutrients that support bone density, such as vitamin D and calcium (4).
• Not just how much you eat, but when you eat matters too. Going for long stretches without food can cause your blood sugar to drop, which signals to the brain that energy is scarce. Since the brain needs a steady supply of glucose to keep reproductive hormones working properly, this can disrupt the release of LH (12).
• Reducing excessive exercise volume and intensity (13).
• Sometimes cognitive behavioural therapy (CBT) can help for individuals with HA who experience psychological stress or for individuals with an eating disorder (13).
• Check-track-manage-learn: Monitoring menstrual patterns, cycle length, ovulation markers, and other changes helps to identify recovery progress.
• Please seek professional support from a qualified healthcare provider, dietitian, and/or psychological therapist if you are experiencing absent periods due to possible HA. 

In short…

If you’re active and health conscious, but find yourself without regular periods, it’s not just “a consequence of being fit.” It may be your body’s way of saying it’s under too much strain.

Restore your cycles by recognising HA, tracking your physiological changes, adjusting your habits, and seeking medical support. By addressing HA fully, you’re not just getting your ovarian cycle and periods back… you’re reclaiming your foundational health.

Main image: Pexels: Photo by Nataliya Vaitkevich.

References

1. Dobranowska K, Plińska S, Dobosz A. (2024) Dietary and Lifestyle Management of Functional Hypothalamic Amenorrhea: A Comprehensive Review. Nutrients.  Sept 3;16(17):2967.
2. Saadedine M, Kapoor E, Shufelt C. (2023) Functional Hypothalamic Amenorrhea: Recognition and Management of a Challenging Diagnosis. Mayo Clin Proc. 98(9):1376–85.
3. Roberts RE, Farahani L, Webber L, Jayasena C. (2020) Current understanding of hypothalamic amenorrhoea. Ther Adv Endocrinol Metab. 11:2042018820945854.
4. Gordon CM, Ackerman KE, Berga SL, Kaplan JR, Mastorakos G, Misra M, et al. (2017) Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 1;102(5):1413–39.
5. Morrison AE, Fleming S, Levy MJ. (2021) A review of the pathophysiology of functional hypothalamic amenorrhoea in women subject to psychological stress, disordered eating, excessive exercise or a combination of these factors. Clin Endocrinol (Oxf). 95(2):229–38.
6. Męczekalski B, Niwczyk O, Battipaglia C, Troia L, Kostrzak A, Bala G, et al. (2024) Neuroendocrine disturbances in women with functional hypothalamic amenorrhea: an update and future directions. Endocrine. 84(3):769–85.
7. Fontana L, Garzia E, Marfia G, Galiano V, Miozzo M. (2022) Epigenetics of functional hypothalamic amenorrhea. Front Endocrinol [Internet]. [cited 2026 Jan 19];13. Available from: https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.953431/full
8. Caronia LM, Martin C, Welt CK, Sykiotis GP, Quinton R, Thambundit A, et al. (2011) A Genetic Basis for Functional Hypothalamic Amenorrhea. N Engl J Med. 364(3):215–25.
9. Shufelt CL, Torbati T, Dutra E. (2017) Hypothalamic Amenorrhea and the Long-Term Health Consequences. Semin Reprod Med. 35(3):256–62.
10. Wade GN, Schneider JE, Li HY. (1996) Control of fertility by metabolic cues. Am J Physiol-Endocrinol Metab. 270(1):E1–19.
11. Wang JG, Lobo RA. (2008) The complex relationship between hypothalamic amenorrhea and polycystic ovary syndrome. J Clin Endocrinol Metab. 93(4):1394–7.
12. De Souza M, Koltun K, Etter C, Southmayd E. (2017) Current Status of the Female Athlete Triad: Update and Future Directions. Curr Osteoporos Rep [Internet]. 15(6). Available from: https://pubmed.ncbi.nlm.nih.gov/29027102/
13. Pape J, Herbison AE, & Leeners B. (2021) Recovery of menses after functional hypothalamic amenorrhoea: if, when and why. Hum Reprod Update. 4;27(1):130–53.
14. Roberts, R. E., Farahani, L., Webber, L., & Jayasena, C. (2020). Current understanding of hypothalamic amenorrhoea. Therapeutic advances in endocrinology and metabolism, 11: 2042018820945854. https://doi.org/10.1177/2042018820945854 
15. King, S. (2024) ‘Black Box: The reduction and mystification of the menstrual cycle in Western school and medical education’. In K. Standing (Ed.) Menstruation: Experiences from the Global South and North. Oxford University Press https://doi.org/10.5871/bacad/9780197267578.003.0003 Available for free here: https://www.researchgate.net/publication/378626892_Black_Box_The_Reduction_and_Mystification_of_the_Menstrual_Cycle_in_Western_School_and_Medical_Education