Where Has My Period Gone?

Amenorrhea: the absence of a period.

Amenorrhea can be divided into 2 categories: Primary and Secondary.

Primary Amenorrhea is where periods don’t start at puberty

Secondary Amenorrhea is where there is absence of a period for 3 months or more in women who have previously had REGULAR cycles. 

Secondary causes of Amenorrhea can be due to hyperprolactinemia, primary ovarian insufficiency, pregnancy, other chronic conditions or Functional Hypothalamic Amenorrhea (which this blog will be focusing on) 

Functional Hypothalamic Amenorrhea (FHA) is the loss of a period caused by under-eating (or not eating enough carbohydrates) /disordered eating, excessive exercise and/or stress. This is a diagnosis of exclusion, meaning other possible factors will have been investigated first.

Under eating, or too little energy of any macronutrient (including carbohydrates, YES, the starchy kind) can switch off the communication from the hypothalamus (a region in the brain) to the ovaries. It is not a malfunction of the body, but it is instead the brain making a smart decision to avoid pregnancy when it doesn’t have the resources to make a baby.

In sports its known as Relative Energy Deficiency (RED) which is the ratio between energy intake, body mass and energy expenditure (exercise)


Do you have to be underweight to lose your period? 

No, women with normal, ‘healthy’ BMIs can also experience FHA. If energy output outweighs energy input, then your body will perceive itself to be in a state of stress, and prioritise where energy should be preserved.

When will my Periods come back?

The hypothalamus is waiting for adequate calorie intake from protein, fats and carbohydrates. Only when the Hypothalamus feels safe, in the form of high energy availability and low physical and mental excursion (STRESS) will it signal to the ovaries to release LH & FSH which stimulate ovulation.

Hormone Birth Control is not an effective treatment for HA because withdrawal bleeds from the pill are not periods. Birth control suppresses your natural hormones, and instead provide synthetic hormones that mimic a natural cycle. The birth control pill does not address the underlying issue of why you are not having a period.

NOTE: If your GP has advised that you take a contraceptive to ‘regulate’ your hormones, please work with a Nutritional Therapist like myself, a dietician or someone that specialises in HA recovery.


Long term impacts of missing periods? 

Long term health risks with FHA include higher risk of cardiovascular disease & compromised bone health. Low Oestrogen suppresses bone production, which can lead to bone loss, increased risk of fractures, osteopenia (loss of bone calcium) and more seriously Osteoporosis. FHA can increase risks of depression, anxiety and infertility. It is important that if you are missing period, and have done for longer than 3 months (and previously had regular periods) you book to see your GP to rule out any underlying conditions. 

How to Get your Period Back

In FHA, menstrual cycles & ovulation usually return when someone begins eating a minimum of 2500 calories (it may be more for some people) reducing intense or excessive exercise, & managing stress levels. It is important to note, that it can take up to 6 months of consistently eating and modifying exercise before periods return.

During Hypothalamic Amenorrhea, vegetables and high fibre diets should take a back seat. Research shows that eating a high fibre diet may actually suppress ovulation by decreasing the enzyme beta-glucuronidase which helps to reabsorb oestrogen around the body.


1.   Eat at least 2500 calories per day

2.   Include starchy carbohydrates such as rice, potato, quinoa, bread with EVERY meal

3.   Eat every 2-3 hours (three meals + three snacks), and do not leave longer than 12 hours between your last meal and your breakfast the next morning.

4.   Reduce all intense and/or endurance exercise. Moderate amounts of walking or gentle yoga may be ok. (this will vary)

5.   Manage stress levels: Meditation, breathing, journaling, social connection

This is a topic that I am extremely passionate about, and is not talked about enough. Missing a period due to FHA is not normal. It is a sign that your body is stressed and needs extra care. As something I have struggled with for a long time, I know how stressful it can be. Please get in touch, if you need help.,