How Do I Know If, and When I’m Ovulating?

This might surprise you, but your period is not the main event of your menstrual cycle.

Yes, managing your monthlies takes some attention (especially if you suffer during this time), but it's actually ovulation that determines if, when, and how your period shows up - and it's a far more complex process than most people realise.

Ovulation occurs when one of your ovaries releases an egg. Women of reproductive age should ovulate every month, but a lot needs to go right for that to happen. It actually takes around 100 days for an egg to fully mature - so the one you release this month began its journey more than three months ago. During that time, you have the opportunity to either support or potentially disrupt the development of the egg and its chances of being released successfully.

What Is Anovulation?

Anovulation or lack of ovulation, is surprisingly common and can happen for various reasons. The intricate hormonal symphony that controls ovulation is highly sensitive to disruption. So, depending on what’s going on in your life or with your health, you might occasionally skip ovulation. That’s normal from time to time, but when it happens regularly, things can start to go haywire, and not just for your periods. Chronic anovulation will affect your overall health and well-being, too.

Why Do We Need to Ovulate?

The obvious reason is, of course, to get pregnant. But even if you're not trying to conceive, ovulation brings with it a whole host of other benefits:

• To maintain a healthy and regular menstrual cycle - Ovulation is key to cycle regularity. Without it, cycles can become erratic or disappear altogether. Irregular menstrual cycles come with a whole host of unwanted symptoms.

  
  

• To produce the hormone progesterone in the luteal phase (the second half of your cycle) - If you don’t ovulate, you won't make Progesterone. This hormone is important for mood stability, sleep quality, and has a calming effect, reducing anxiety. It's important for inflammation control, pregnancy, and reduces heavy periods. We also need Progesterone to make Testosterone.

  
  

• Metabolic health - Ovulation and the associated hormonal fluctuations of oestrogen and progesterone support insulin sensitivity and regulate metabolism and appetite.

  
  

• Bone health - Both oestrogen and progesterone help protect against bone loss and support bone density. 

• Cardiovascular health - Ovulatory cycles are linked to better heart health, with women having a longer reproductive lifespan and regular ovulatory cycles having a reduced risk of heart disease.

  
  

• Brain health - The production of hormones like oestrogen and progesterone at ovulation also support mood, memory, and cognitive function.

  
  

• Libido - Ovulation usually boosts libido - your body’s way of encouraging reproduction, but also a sign of hormonal harmony.

Why Tracking Ovulation Matters

Understanding your menstrual cycle and knowing when you ovulate can help you avoid pregnancy or pinpoint your fertile window when trying to conceive (TTC). But it’s important to track it the right way.

Cycle tracking apps are popular, but most of them calculate ovulation based on the average menstrual cycle length. This method isn’t reliable because your ovulation can’t be confirmed just by knowing when your period starts.

A Quick Overview of the Menstrual Cycle

The menstrual cycle can be broken down into four main phases:

1. Follicular Phase – before ovulation

2. Ovulatory Phase – ovulation itself

3. Luteal Phase – after ovulation

4. Menstrual Phase – your period

   
   

For this post, I’m going to focus on the follicular and luteal phases, since the other two are wrapped up within these.

The Follicular Phase 

The follicular phase begins on day one of your period and lasts until ovulation. This phase is the final stage of follicular development, as these follicles have a much longer lifespan and take 100 days to mature in total. 

During this time, your ovaries respond to a pituitary hormone called FSH (follicle-stimulating hormone) by producing follicles - small fluid-filled sacs. As these follicles grow, one becomes dominant. This is the follicle that will release an egg during ovulation, and it also becomes the primary source of oestrogen (Estradiol)  production.

Oestrogen is the queen bee of hormones. When it’s produced at healthy levels it boosts serotonin and dopamine production, making you feel pretty fabulous. It thickens the uterine lining and stimulates the production of fertile cervical mucus. It also increases libido in the lead-up to ovulation. Clever, right? The dominant hormone at your most fertile time makes you feel sexier and creates nature’s ultimate lube.

Just before ovulation, oestrogen peaks. In the presence of rising levels of oestrogen, FSH triggers a surge in another pituitary hormone—LH (luteinizing hormone). LH surges around 24–36 hours before ovulation, triggering the release of the egg. Once this happens, oestrogen drops, and you transition into the luteal phase.

The length of your follicular phase can vary, lasting anything from 7 to 21 days. 

The Luteal Phase

After the egg is released, the leftover follicle on your ovary becomes a temporary structure called the corpus luteum. This glandular structure now starts producing progesterone.

Progesterone brings a more calming vibe compared to oestrogen. You might feel less energetic, less social,  more inclined to slow down, and your appetite may increase. Sex drive takes a back seat, and your cervical mucus will shift, becoming thicker and less watery, maybe even disappearing altogether.

Progesterone supports the uterine lining, making it nutrient-rich and ready to welcome a fertilised egg. It also plays a critical role in embryo implantation and will continue to support early pregnancy until the placenta takes over hormone production.

If no fertilised egg implants, both oestrogen and progesterone levels will drop around 10–14 days after ovulation. This hormonal decline triggers the shedding of the uterine lining- aka your period. And then the whole cycle starts again.

The Luteal phase should last from 10-14 days. If any longer than this, you may not have ovulated. If shorter, you may have still ovulated, but this will be classed as a short luteal phase and you won't make enough progesterone - this can impact fertility and also menstrual health. 

Can I Still Have a Period If I Don’t Ovulate?

Yes - but it's technically not a true period. What you may experience is a breakthrough bleed, where the endometrial lining sheds without ovulation. This is what's happening when taking the combined oral contraceptive pill (COCP), as this prevents ovulation but still allows for a withdrawal bleed during the pill-free days.

Why Might I Not Be Ovulating?

Ovulation relies on a delicate hormonal balance. Disruptions to this system can be caused by:

• Stress

• Low or high body weight

• Blood sugar imbalances

• Inflammation or illness

• Disordered eating

• Medications

• Sleep disruption, shift work, or travel

• And of course, pregnancy

  
  

These factors can delay or prevent ovulation altogether, especially if they're ongoing.

How do I know when I am ovulating and which tests to use?

A combination of methods is often most effective. Here are several ways to track your fertile window and confirm if you're ovulating:

1. Ovulation Predictor Kits (OPKs)

These test for a rise in luteinizing hormone (LH) in urine, which peaks 24–36 hours before ovulation. However, they need to be timed well and are less reliable for women with PCOS, as LH may be persistently elevated.

Tip: Watch for fertile signs like cervical mucus before beginning OPK testing and then use these tests daily until you see a clear change of colour or smiley face (depending on the brand) on the test strip indicator confirming the day of ovulation.

2. Basal Body Temperature (BBT) Charting

Your BBT increases after ovulation due to a rise in progesterone. Using a BBT thermometer:

• Take your temperature first thing each morning (before moving or getting up).

• Track it daily from day 1 of your cycle. This is the first day of your period with full blood flow (spotting doesn't count).

• A temperature shift mid-cycle suggests ovulation has occurred.

• You should see a biphasic pattern with a rise in temperature of around 0.2C in the 3 days following ovulation. This rise in temperature should remain consistent for around 10 days.

  
  

Note: Illness, alcohol, or irregular sleep can affect readings. Apps or wearable devices can help automate the process.

3. Fertility Awareness Method (FAM)

FAM combines BBT tracking with cervical mucus observation and sometimes cervical position checks.

• Fertile mucus is clear, slippery, and egg-white-like - your body’s natural sign that ovulation is near.

• Cervical position may also rise and soften around ovulation.

  
  

Fertile mucus is capable of keeping sperm in a prime position for up to 5 days. With this in mind, you are most fertile on the days leading up to ovulation, when this mucus is present, on the day of ovulation, and for 1-2 days following ovulation. This equates to around 6 days in total. When learned correctly and with practice, FAM is highly effective.  

This method is not for everyone, as tracking your BBT can be stressful, particularly if you are TTC. 

4. Hormone Blood Testing

To confirm ovulation via blood work,  progesterone levels need to be tested  7 days after suspected ovulation (Ovulation + 7). You will need to use a combination of the above methods to time this right. 

For deeper insights, I always test FSH, LH, and oestrogen between days 2–3 of your cycle. This helps identify issues with the start of your cycle that could be impacting your ovulation. 

In perimenopause or PCOS, hormone testing can be trickier - it's best to work with a fertility-awareness practitioner or fertility nutritionist to support you with this. 

Tip: Day 21 progesterone test - most GPs, when testing progesterone, will standardly do this on day 21 of your menstrual cycle. This is only accurate if you are having a textbook 28-day cycle and ovulating on day 14. As we know cycle length and time of ovulation can vary.

5. Follicle Monitoring Scans

Ultrasound scans can confirm ovulation by visualising the developing and released follicle. This method is used in clinical settings - ideal during fertility treatment or when investigating irregular cycles, but not practical for monthly self-monitoring.

What’s the Best Way to Track Ovulation?

If budget allows, wearable digital devices that monitor temperature (like Oura Ring or Tempdrop) offer convenient and accurate ovulation tracking.

Otherwise, the best method is a combined approach:

• Observe cervical mucus to pinpoint your fertile window (remember this is around 6 days)

• Use OPKs at the onset of your fertile window  (when fertile mucus is noticeable) to identify the day of ovulation.

• Confirm ovulation with BBT and/or blood tests. Working with a practitioner to help you with it is generally needed in the early stages.

  
  

If your cycles are irregular or absent, ovulation may be infrequent or missing. You should always consult with your GP if you are experiencing symptoms of anovulation in order to rule out any conditions that may require medical treatment. Also don't forget to consider a potential pregnancy.

If you would like nutritional support with optimising your ovulation and your menstrual cycles please get in touch.

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References:

Wang, Y.X., Arvizu, M., Rich-Edwards, J.W., Stuart, J.J., Manson, J.E., Missmer, S.A., Pan, A. and Chavarro, J.E., 2020. Menstrual cycle regularity and length across the reproductive lifespan and risk of premature mortality: prospective cohort study. BMJ, 371, p.m3464. Available at: https://pubmed.ncbi.nlm.nih.gov/32998909/ [Accessed 9 May 2025].

Briden, L., 2017. Period Repair Manual: Natural Treatment for Better Hormones and Better Periods. 2nd ed. GreenPeak Publishing.​

Reed, B.G. and Carr, B.R., 2018. The normal menstrual cycle and the control of ovulation. In: K.R. Feingold, S.F. Ahmed, B. Anawalt, et al., eds. Endotext [online]. South Dartmouth (MA): MDText.com, Inc. Available at: https://www.ncbi.nlm.nih.gov/books/NBK279054/ [Accessed 9 May 2025].​

Femometer, n.d. 5 Basic Things You Should Know about BBT Charting. [online] Femometer. Available at: https://www.femometer.com/Blog/5-Basic-Things-You-Should-Know-about-BBT-Charting [Accessed 9 May 2025].