Our periods are sometimes late because our ovulation was delayed. But how do we determine ovulation? And minimize the impact of stress on our cycles?


Wouldn’t it be great to always know exactly when to expect your period, instead of anxiously waiting day-by-day for a late period?

Even if your period is irregular, occasionally or often late?

What if I told you there was a way to definitely determine the beginning of a new cycle, every month, no matter the circumstances?

By consistently charting body basal temperature (by taking temperature first thing on waking up) and successfully determining when ovulation occurs, we can learn to read our body’s signs so intimately so as to remove the guesswork from menstruation.


Why ovulation?

For a deeper understanding of the menstrual cycle, we need to look more closely at the relationship between ovulation and menstruation.

Ovulation and menstruation are two events that mark the beginning and end of two distinct phases of our cycle: the follicular phase (from cycle day one until the day of ovulation) and the luteal phase (from the day after ovulation until the day before menstruation).

The length of the follicular phase is susceptible to environmental factors, such as stress, which delay ovulation and make this phase indefinite in length. Estrogen is the dominant hormone in this phase.

The length of the luteal phase is a relatively constant 12-16 days. Progesterone is the dominant hormone in this phase. Progesterone is necessary for menstruation to occur, and its production is entirely dependent on the process of ovulation. 

Without ovulation, there is no menstruation.

An irregular or late period is most likely caused by delayed ovulation, due to stress.


So what exactly is ovulation? And why is it necessary for menstruation?

Ovulation is the process where the fully developed ovum leaves the ovary and makes its journey through the Fallopian tubes and into the uterus where it stays for about 24 hours. If the egg is not fertilized within this time it will disintegrate.

Estrogen, testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) all work together to grow and release an ovum (or egg), and for ovulation to occur. After the egg is released, the follicle in which it had been growing seals itself off and forms a structure known as the corpus luteum. The corpus luteum and the hormone it produces, progesterone, are responsible for continuing to build up the uterine lining (endometrium), and, if the egg is fertilized, for implantation and assisting in maintaining pregnancy.

If the egg is not fertilized the corpus luteum takes about two weeks to break down, which is when progesterone levels drop and cause the shedding of the endometrium. This is menstruation.

Until after ovulation has happened there is no progesterone production and therefore no period.

Once ovulation has happened, menstruation can, with some certainty, be expected 12-16 days later.

Everyone’s luteal phase is relatively constant for them. Once you determine the length of your luteal phase, you can, in the absence of major life changes, expect it to remain constant.


But why is my ovulation late?

Ovulation is a highly sensitive process and can be delayed by any number of minor or major stressors.

Our bodies want to make life, and they want to create the best conditions for making life. Because of our biological nature, our bodies are easily influenced by stress when it comes to reproduction. Imagine our early human ancestors: if they were running from a Sabre-toothed tiger, would that be the best time to make a baby? Nope, that stress would tell the body to hold off ovulation until conditions were more suitable and calm.

The body may have multiple attempts at ovulation before it actually occurs. These attempts may come with all the other signs of fertility: increased cervical fluid, open cervix, feeling strong and sexy but at the last minute, due to one or other stressor, actual ovulation may not take place, no egg is released and no corpus luteum develops. When this happens, the body may take a couple days and try again. It may try any number of times until it is successful, extending the follicular period indefinitely.

Here are some more modern-day stressors that could delay ovulation:

  • Travel
  • Alcohol
  • Caffeine
  • Sugar
  • Insufficient sleep
  • Over-exercising
  • Overworking, work stress
  • Relationship or family stress
  • Digestive issues, especially constipation
  • Illness (physical or mental), injury, infection or inflammation
  • Trauma or grief, past or present
  • Antibiotics, drugs or pharmaceutical contraceptives
  • Lack of nutrients, malnourishment
  • Hormone imbalance

The body does not distinguish between stressors. The body’s stress response is the same whether the stress is physical or emotional, internal or external, seemingly minor or major.

It takes up to 100 days for an ovum to fully develop, which means that stressors from three months ago could influence your current cycle.


Ok so my period is late because of ovulation being delayed by stress, but how do I confirm ovulation? And how do I build resilience to these very common stressors?

The only way to confirm that ovulation has occurred, without a well-timed ultrasound, is by consistently charting basal body temperature (BBT).

Estrogen keeps our basal body temperature relatively low during the follicular phase of our cycle. After ovulation has occurred, progesterone warms the BBT by more than 0.4C (in an optimal cycle). After three days of consistently higher temperatures, we can confirm that ovulation has definitely taken place.

After consistently charting your temperature for about three cycles, you should be able to calculate the length of your luteal phase (the number of days between ovulation and menstruation) and, by confirming ovulation each cycle, easily predict when to expect menstruation even in the case of illness or stress. 

Another benefit of charting BBT is that there is often a significant temperature drop the day of menstruation, so as soon as you wake up you can make preparations for the day.

Of course stressors are inevitable but we can build resilience and give our bodies the best chance at “bouncing back” from stress. Some of my favorite everyday stress resilience techniques include:

  • Mindful walking, breathing, meditation
  • Yoga (be careful of power yoga, vinyasa, bikram or other intense classes)
  • Submerging in natural water: oceans, rivers, rainwater baths
  • Forest bathing, being in nature, gardening
  • Walking barefoot on sand or soil
  • Aromatic plant-based meals
  • Satisfying sex
  • Support and touch from a loving friend
  • Singing, humming, omming, dancing, music (especially live music!)
  • Herbal teas
  • A glass or two (no more!) of organic red wine
  • Knowing and practicing the limits and capabilities of each phase of your cycle


Your body is doing its best

It is easy to get frustrated at our bodies when they’re not working like clockwork, but remember, we are not machines. We are complex living organisms made up of a multitude of interconnected systems. Engaging in a practice where we listen to our bodies’ subtle communications can assist in telling us when something is not quite right and to, through nutrition and lifestyle choices, support our bodies to keep doing their thing.

We tend to think of menstruation as the main event of our cycle (maybe because of all the pain, blood, emotions and social taboos) but it is in fact ovulation that is the main event and driver of our hormonal cycle. Understanding ovulation, its relationship to menstruation, and the different energies of the follicular and luteal phases, are vital steps in building a compassionate and affirming relationship with your cycle.

No matter where you are in your journey to hormonal harmony and a balanced cycle remember to practice compassion for your body and yourself, the way you would for a dear friend.


Charting BBT is an incredible tool for communicating with our bodies: not only for determining ovulation and predicting menstruation, but for reading underlying health issues. It can also be used as a tool in Fertility Awareness Based Methods of contraception, ideally with the guidance and support of a qualified coach. The method described here is intended for health reasons only, not for contraception. Here at Hormonal Harmony we recommend every woman who wants to deepen her relationship with her body, to invest in a body basal thermometer and begin charting her waking temperature. If you are interested in pursuing for FAM for birth control please reach out to us.