Subclinical Ovulatory Disturbances

Adaptation of menstrual cycle hormones

In my book “Hormones, Health and Human Potential”, I really enjoyed writing the chapter 5XX “Of Mice and men….and Women!” Celebrating Horme the goddess of effort, energy and action. However, there are some instances where even this formidable goddess is challenged and adaptations are required[1].

Challenges to menstrual cycle hormones

Menstrual cycle hormone choreography is as beautiful as it is complex. Generally, this repeating motif follows the score faithfully during a woman’s reproductive years. However, when external stressors become too great, then menstrual hormone fluctuations respond and adapt.

A single stressor, for example financial concerns or a life event can impact hormones and disrupt menstrual cycles on a short time scale of a handful of cycles. However, a combination of stressors can have a synergistic effect on disrupting female hormone networks. Additive stressors over a long-time scale are known as an allostatic load. A high allostatic load causes a more extensive adaptation of female hormones[2]. For example, a high level of stress from intense exercise training together with metabolic stress from insufficient food intake can result in total suppression of menstrual cycle hormone fluctuation and cessation of periods (amenorrhoea) found in relative energy deficiency in sport (RED-S).

Unbalanced behaviours

Although “hormone imbalance” is a popular phrase, this has no medical meaning. This misleading phrase does a massive disservice to Horme and to millions of years of evolution in fine-tuning the most intricate hormone network. It is not the hormone network that has become “unbalanced”, rather it is our unbalanced behaviours and/or management of external stressors that have caused hormones to adapt and change appropriately. On a positive note, understanding hormones empowers us to nurture and harness our hormones through our lifestyle choices.  

Spectrum of female hormone adaptation

There is a graded response of female hormones to external stressors, depending on the number and the time scale of these. A cumulative combination of stressors results in a high allostatic load which causes amenorrhoea. Physiological causes of amenorrhoea must be excluded: pregnancy and menopause; as should medical causes such as prolactinoma and polycystic ovary syndrome (PCOS).

The type of amenorrhoea occurring as an adaptive response to a high allostatic load is functional hypothalamic amenorrhoea (FHA). This means that the neuroendocrine gatekeeper in the brain, the hypothalamus, has taken the executive decision to suspend female hormone fluctuations, in order to conserve resources to deal with the stressful situation. From an evolutionary point of view this is not the time for the high demand state of pregnancy. The good news is that being an adaptive functional response, FHA is reversible if the underlying cause is addressed.

Tip of the iceberg

Amenorrhoea is a very obvious clinical sign. Similarly, oligomenorrhoea (less than 9 periods per calendar year). However, these menstrual disruptions are just the tip of the iceberg. Less obvious are the subclinical ovulatory disturbances (rather unflatteringly referred to as SODs). This is where a women may experience a menstrual period, but the full repertoire of female hormone fluctuation has not occurred. Specifically, progesterone has not increased to levels that would be expected in the luteal phase of the cycle (second half of the cycle). If ovulation has occurred, then the remnant of the egg follicle in the ovary forms the corpus luteum which secretes progesterone. Progesterone increases resting metabolic rate and energy demand. So, keeping progesterone low is a good adaptive response to high allostatic load by keeping energy demand low.

If subclinical ovulatory disturbances are an adaptive physiological response, does this matter for a woman’s health? The answer is yes. Oestradiol (the most active form of oestrogen) often takes the limelight when it comes to positive effects on bone, soft tissue, cardiovascular, and neurological health. However, evidence is emerging that progesterone plays an equally important supporting role in these areas of health. For this reason, it is important to identify these elusive disturbances in menstrual hormone choreography.

How to detect subclinical ovulatory disturbances

As I discuss in my book in the chapter “Hormone Supermodels”, applying artificial intelligence (AI) techniques to modelling menstrual cycle hormones can help in identifying subtleties in hormone disruption. This is a fast-moving field and even since publishing on this topic, further advances are being made as more data is emerging and employment of different mathematical techniques, with reduction in the number of samples required. Monitoring temperature change as surrogate for indicating adequate progesterone levels during the luteal phase is a non invasive way of monitoring menstrual cycle hormone function. Personalisation of female hormone health is on the move. Nevertheless, the cornerstone of any medical AI focused on hormones is the medical doctor with expertise in hormones, putting the results in clinical context for the individual. Explaining and advising with practicality and empathy is vital.

This personalised medical approach is crucial when, by definition, subclinical ovulatory disturbances will require guidance on changing behaviours to reverse adaptive hormone changes. When I work with athletes and dancers experiencing hormone disruption due to imbalances in exercise and nutrition, I find it helpful in referring to recovery from a hormone injury as comparable to recovering from a physical injury. Furthermore, there can be a psychological dimension to subclinical ovulatory disturbances. How we interpret external events and think impact our hormones. For example, cognitive dietary restraint (just thinking you should eat less/be thinner) can cause subclinical ovulatory disturbances.

Nurturing Horme

Menstrual cycle hormone choreography is the most intricate and beautiful of all the hormone networks. There is a spectrum of hormone adaptation according to the degree of “stress” put on the system. The visible tip of the iceburg is menstrual disruption such as amenorrhoea and oligomenorrhoea. Less obvious, beneath the surface are subclinical ovulatory disturbances. Subclinical ovulatory disturbances are adaptive hormone responses to unbalanced behaviours and/or interpretation of external events. These subtleties of subclinical ovulatory disturbances can be challenging to identify. However, it is important to do so and provide appropriate medical support to restore these hormones for long term health.

[1] Keay N. Hormones, Health and Human Potential 2022 Sequoia books

[2] Prior J. Adaptive, reversible, hypothalamic reproductive suppression: More than functional hypothalamic amenorrhea Front. Endocrinol 2022 Sec. Reproduction

Hormone Knowledge is Power

Hormones are the directors of health, enabling us to reach our personal full potential. To unlock the power of hormones and harness our hormone networks, we need to be empowered with understanding. This was the motivation for my book “Hormones, health and Human Potential: A guide to understanding your hormones to optimise your health and performance

I was one of the panel discussing hormone power at Bloomfest last week. I started by suggesting that if you are ever labelled as being “hormonal”, take this as a compliment. After all, Horme is the goddess of action and energy. We discussed how to navigate the lifetime female hormone odyssey

Female Hormone Choreography

Hormone networks are complex. Out of all the networks, those of the female hormones is the most intricate. A beautiful interactive dance of hormones occurs every menstrual cycle, following characteristic choreography. However, this hormone dance will be personal to each woman, with subtleties in timing, hormone levels and crucially individual biological response. This is why knowledge is power when it comes to female hormones. Tuning into your personal variation of hormones in terms of how you feel, takes away the mystery. This empowers you to be proactive and work with your hormones, not against them. Periods are the barometer of internal hormone health and a free monthly medical check. I mentioned the potential flash points of the menstrual cycle in terms of menstruation and the luteal phase (occurring after ovulation, in the 2 weeks or so before menstruation) and practical strategies to put in place. This area is discussed in detail in Act 1, Scene 5XX “Of Mice and Men….and Women”.

Hormonal Contraception

Hormonal contraception is often an area of confusion. It is every woman’s choice regarding her personal choice of contraception. However, in order to make an informed choice about the most suitable form, it is really important to clarify the different types available. Non hormonal options, barrier methods include condoms and the copper coil. Hormonal contraception can be divided into combined (synthetic oestradiol and progesterone) and synthetic progesterone-only options. Incidentally a hormonal contraception was trialled men, but they didn’t not like the side effects. As I explain in my book, it is really important that women (and their doctors) know that combined hormonal contraception (eg combined oral contraceptive pill) and certain types of synthetic progesterone-only options, suppress the internal production of female hormones across the board. This is why these medications are very effective contraception. This suppression of internal female hormones can be very useful for women with endometriosis and polycystic ovary syndrome (PCOS) which are conditions effectively fuelled by female hormones. However, this suppression of female hormones is absolutely not suitable for women whose periods have stopped. After writing to NICE, I am pleased to report the guidelines are now updated to advise against giving hormonal contraception to women who are not experiencing periods.

Hormone Injury

Unbalanced external lifestyle choices, rather than harnessing hormones, can cause female “hormone injury”. In my book Act 1, Scene 10 “In the Red” goes into the detail of how an imbalance in behaviours around exercise and nutrition can derail female hormone choreography. I outline practical advice of how to recover from this type of “hormone injury” and what to do to restore and reboot hormone networks and return to full health.

Graduation to Menopause and beyond

Variation in female hormone choreography occurs over the longer time scale of a woman’s lifespan. Menopause is a hot topic. Although it is great to see this being discussed, I suggest we need a more positive narrative. I prefer to talk about the graduation to menopause, rather than a decline. This stage in a woman’s life is something I cover in depth in my book in Act 2 looking through the “The Seven Ages of Man and Woman”. In some cultures, being older and wiser is revered. Menopause is something that all women will experience during their life. A point in time when the ovaries retire in their production of hormones and release of eggs.

The graduation to menopause can be the most challenging. During the perimenopause the ovaries work on an unpredictable, part time basis. The female hormone choreography works smoothly in some cycles. Other cycles there will be a mistiming and confused choreography, causing some of the typical indicators of menopause. These include changes in cycle length and nature, temperature regulation issues, labile mood and brain fog being some of the most frequent. We discussed that probably the most helpful approach for women in the workplace is to facilitate discussions, sharing experiences and putting in place practical things that are helpful for the individual: for example, having a desk fan nearby, sitting near a window. From the medical support point of view, providing the facts and practical aspects of taking HRT is something that I am very pleased to be able to provide.

The quote from the Vice President of the Royal College of Obstetrics and Gynaecologists: “Treat women as individuals, not statistics” is something that resonates when it comes to discussing how to unlock and harness the power of female hormones, throughout each woman’s personal female hormone odyssey.


Hormones, Health and Human Potential: A guide to understanding your hormones to optimise your health and performance”

Effects of adaptive responses to heat exposure on exercise performance

To date few studies have been conducted on the effect of heat exposure to exercise performance in female athletes. With the publication of recent research, hopefully this will now change with the 2018 Commonwealth Games to be held in Queensland, Australia where athletes will have to compete in hot conditions.womenarenota

A picture of the author Tze-Huan Lei and participant while taking part in the experiment. Credit: David Wiltshire, Massey University, New Zealand

During the luteal phase (post ovulation, when progesterone levels rise) of the menstrual cycle, body temperature rises. Hence the previous suggestion “that women should avoid competition or face a disadvantage when performing exercise with heat stress during their luteal phase”. However recent research demonstrates that in eumenorrheic athletes, autonomic regulation of body temperature (skin blood flow and sweating) either at rest or during exercise is not effected by the phase of the menstrual cycle. As yet there are no studies of females athletes taking the oral contraceptive pill with respect to body temperature regulation.

A recently published study, conducted on male athletes demonstrated that episodic heat exposure over 11 days had a positive effect on regulating body temperature in hot conditions, associated with rapid onset of sweating. This heat exposure also increased skeletal muscle contractility. These findings suggest that heat adaptation could maintain and improve sport performance. The mechanism of this improvement in skeletal muscle contractility with heat exposure could be an increase in transcription of oxidative phosphorylation-associated genes resulting in increases in synthesis of ATP, muscle mass and strength. This effect was recorded amongst men exposed to 10 weeks of periodic heat stress, without any training. In other words heat alone, even without exercise improved skeletal muscle function.

The interesting findings of these studies investigating the adaptive responses produced by exposure to heat will hopefully stimulate further research to include female athletes who compete in the same challenging environmental conditions as male athletes.

For further discussion on Endocrine and Metabolic aspects of SEM come to the BASEM annual conference 22/3/18: Health, Hormones and Human Performance


Physiological Society report

The Journal of Physiology

Amercian Journal of Physiology

European Journal of Applied Physiology