If your period has become increasingly irregular, or disappeared altogether, it can be easy to focus only on your reproductive hormones.
But sometimes, a missing period is less about a problem with your ovaries and more about your brain deciding that your body doesn’t currently have the resources it needs to prioritise reproduction.
This is known as functional hypothalamic amenorrhoea (FHA), or hypothalamic amenorrhoea (HA).
At Pure Health Nutrition, we often describe the menstrual cycle as a monthly report card. Your cycle responds to much more than reproductive hormones alone: it can give us insight into whether your body is receiving enough energy, nutrients and recovery to meet its current demands.
What is hypothalamic amenorrhoea?
Hypothalamic amenorrhoea occurs when communication between the brain and ovaries becomes suppressed.
Your hypothalamus, a small region of the brain, normally releases gonadotropin-releasing hormone (GnRH) in pulses. GnRH signals the pituitary gland to produce luteinising hormone (LH) and follicle-stimulating hormone (FSH), which then communicate with your ovaries and help regulate follicle development, ovulation and oestrogen production.
With HA, these GnRH pulses slow down or become disrupted.
As a result:
GnRH decreases → LH and FSH signalling is altered → ovarian activity decreases → oestrogen can fall → ovulation and menstruation can stop.
HA is considered a functional condition because there is not necessarily something structurally wrong with your hypothalamus, pituitary gland or ovaries. Rather, the reproductive system has adapted to signals suggesting that conditions are currently unsuitable for reproduction.
Why causes hypothalamic amenorrhoea?
There generally isn’t one single cause.
The three major factors associated with HA are:
- Low energy availability
- High levels of physical activity or exercise
- Psychological or physiological stress
And, commonly, it is a combination of all three.
1. Not eating enough for your body’s needs
One of the biggest drivers of HA is low energy availability.
Energy availability is essentially the amount of energy left for your body to perform its normal physiological functions after accounting for the energy used during exercise.
Your body requires energy for far more than movement. It needs energy for your brain, heart, immune system, digestion, thyroid function, bone turnover, temperature regulation, and your reproductive system.
If dietary intake repeatedly fails to meet your total needs, your body starts making decisions about where that energy should go.
Keeping you alive is essential.
Ovulation isn’t.
Over time, reproductive hormone signalling may therefore be downregulated.
This can occur because someone is intentionally dieting, but it can also happen completely unintentionally. You might be eating a nutritious diet and still simply not be eating enough to match the amount you are training, walking, working and living.
This is why HA can occur at a range of body sizes. You do not need to look underweight for your body to be experiencing low energy availability.
2. Exercising more than your body can recover from
Exercise itself isn’t the enemy.
Movement is incredibly beneficial for physical and mental health. The issue arises when exercise demands consistently outweigh the body’s ability to fuel and recover from them.
This may look like:
- Running several times per week
- High-intensity training most days
- Long endurance sessions
- Combining strength training with significant cardio
- Maintaining very high daily step counts
- Rarely taking complete rest days
- Continuing to train intensely while simultaneously reducing food intake
The question we often need to ask is not simply, “Do you exercise too much?”
It is:
“Are you adequately fuelling and recovering from the exercise you’re doing?”
Two women can complete the exact same training program and have very different hormonal responses depending on their nutrition, sleep, stress levels, genetics and overall energy availability.
3. Your body is experiencing too much stress
The brain doesn’t separate stress into neat categories.
Psychological stress, work pressure, relationship stress, inadequate sleep, restrictive eating, under-fuelling and intense exercise can all contribute to the body’s overall stress load. This is where the HPA axis, the hypothalamic-pituitary-adrenal system involved in our stress response, and the reproductive HPO axis, the hypothalamic-pituitary-ovarian system that regulates ovulation and the menstrual cycle, can interact.
In some women susceptible to HA, heightened stress signalling can interfere with the pulsatile release of GnRH required for normal reproductive function. This is also why nutritional recovery alone isn’t always enough. You may need to consider whether your body is receiving genuine opportunities to feel safe, rested and recovered.
And no, this doesn’t mean you need to eliminate all stress from your life. It means intentionally creating more capacity for recovery.
Sometimes this looks like meditation or yoga. Other times, it looks like cancelling a workout, sleeping an extra hour, going for a gentle walk, reading a novel, cooking, spending time with friends or doing something simply because you enjoy it.
Rest and joy are an essential part of treatment.
What are the signs of hypothalamic amenorrhoea?
Hypothalamic dysfunction can affect the menstrual cycle before your period disappears completely. You may first notice changes such as:
- Periods becoming further apart
- Difficulty identifying or confirming regular ovulation
But other signs can accompany HA, particularly when low energy availability is present.
You may also notice reduced libido, fatigue, feeling cold, poorer exercise recovery, recurrent injuries, sleep disturbances, changes in mood or difficulty improving training performance. Not everyone will experience all of these symptoms.
Why getting your period back matters
A regular menstrual cycle isn’t only important if you are trying to have a baby. One of the biggest concerns with prolonged HA is low oestrogen. Oestrogen plays an important role in maintaining bone health. When oestrogen remains low for an extended period, bone mineral density can decline and the risk of stress fractures and longer-term skeletal problems can increase. HA also means that ovulation may not be occurring regularly, which can affect fertility.
Current Endocrine Society guidance recommends considering a baseline bone mineral density scan in women who have experienced amenorrhoea for six months or longer, or earlier where significant nutritional deficiency or skeletal fragility is suspected.
Your period is not an option. It provides valuable information about how your body is functioning.
How is hypothalamic amenorrhoea diagnosed?
It’s important not to assume that a missing period is HA.
Hypothalamic amenorrhoea is a diagnosis of exclusion, meaning other potential causes of an absent menstrual cycle need to be investigated first. Depending on your individual presentation, investigation may consider:
- Pregnancy
- PMOS
- Thyroid dysfunction
- Elevated prolactin
- Primary ovarian insufficiency
- Pituitary conditions
- Other endocrine or reproductive conditions
Blood testing may include markers such as LH, FSH, oestradiol, prolactin, TFT and antibodies, alongside other pathology based on your symptoms and history.
Your practitioner should also look beyond the blood test. Understanding your menstrual history, weight changes, dietary intake, exercise routine, sleep, stress, relationship with food and previous fractures can provide crucial pieces of the puzzle.
Supporting recovery from hypothalamic amenorrhoea
The goal isn’t simply a return of the menstrual cycle. The goal is to address the signals that caused reproductive function to be suppressed in the first place.
Eat enough, and eat consistently
Correcting an energy imbalance is considered a cornerstone of HA treatment. This may require increasing overall food intake, improving nutrition, reducing exercise expenditure, or a combination of all three. For many women, that means moving away from long fasting windows, skipped meals and consistently “light” meals.
A helpful starting structure may include three substantial meals each day + regular snacks where required.
Carbohydrates are particularly important when energy availability and reproductive hormone signalling are concerns. This isn’t the time to fear rice, potatoes, oats, bread, fruit or other carbohydrate-containing whole foods.
Meals ideally contain a combination of:
Protein + carbohydrates + healthy fats + fibre.
And yes, dietary fat matters too. Extremely low-fat diets are not appropriate when supporting the return of a menstrual cycle.
Reassess your relationship with exercise
You don’t necessarily have to stop all movement. But recovery may require reducing training volume or intensity for a period of time. That could mean replacing a high-intensity session with walking, introducing additional rest days, reducing running volume or shortening workouts.
The right amount will be individual.
Schedule intentional rest
If rest only happens when everything else on your to-do list is finished, chances are it doesn’t happen often. So put it in your calendar. Schedule the walk with a friend. Book the massage. Take the slow Sunday morning. Read the book. Go to the beach. Do yoga. Cook. Paint. Spend time outside.
Whatever genuinely allows your nervous system to come down from being constantly “on”, make space for it, with intention.
Recovery is something we often need to practise, particularly if productivity and exercise have become closely tied to our sense of achievement.
Support bone health
Where periods have been absent for an extended period, bone health should also form part of the conversation.
Alongside restoring adequate energy availability and reproductive hormone function, your practitioner may assess your intake or blood levels of nutrients involved in skeletal health, including calcium and vitamin D, while ensuring adequate overall protein and nutrition.
How long does it take to get your period back?
There is no standard timeline. For some women, menstrual cycles begin returning relatively quickly once adequate nutrition and recovery are established. For others, particularly where restriction, high training loads or stress have been present for years, recovery can take significantly longer.
Your first cycle may also not immediately look “perfect”. Ovulation and cycle length can take time to regulate as communication across the HPO axis resumes.
The important thing is to look at the bigger picture rather than trying to force the body into a deadline.
Where to start
If your period has disappeared, we want to nourish the hypothalamus.
More food. More recovery. More sleep. Less pressure. More safety.
At Pure Health Nutrition, our Clinical Nutritionists and Naturopaths take a whole-body approach to menstrual health. We investigate potential drivers of irregular or absent periods through pathology, nutrition, exercise, stress, sleep and health history, before creating individualised treatment plans designed to address the underlying cause.
If your periods have become irregular or have disappeared altogether, book an appointment with the Pure Health Nutrition clinic to investigate what may be driving the change and receive personalised support to restore healthy menstrual function.
This article is for educational purposes only and does not replace individual medical advice. Amenorrhoea should be appropriately investigated by your GP or healthcare practitioner.
References
Briden L. Period Repair Manual: Natural Treatment for Better Hormones and Better Periods. Pan Macmillan Australia. 2018.
Dobranowska K, Plińska S, Dobosz A. Dietary and Lifestyle Management of Functional Hypothalamic Amenorrhea: A Comprehensive Review. Nutrients. 2024. https://pubmed.ncbi.nlm.nih.gov/39275282/
Endocrine Society. Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline. 2017. https://www.endocrine.org/clinical-practice-guidelines/hypothalamic-amenorrhea?ut
Mountjoy M, et al. 2023 International Olympic Committee’s consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine. https://bjsm.bmj.com/content/bjsports/57/17/1073.full.pdf?
Roberts RE, Farahani L, Webber L, Jayasena C. Current Understanding of Hypothalamic Amenorrhoea. Therapeutic Advances in Endocrinology and Metabolism. 2020. https://pubmed.ncbi.nlm.nih.gov/32843957/
Shufelt CL, et al. Functional Hypothalamic Amenorrhea: Recognition and Management of a Challenging Diagnosis. Mayo Clinic Proceedings. 2023. https://pubmed.ncbi.nlm.nih.gov/37661145/