Ovulation And Fertile Window

How do I know when there is ovulation to determine my fertile window? 

There are several methods to determine your ovulation and fertile window. You can track the length of your cycle, know your secretions, test your urine to detect when you may be approaching ovulation, and chart your temperature. Let’s explore these in more detail.

1. Tracking your cycle length to discover your ovulation and fertile window

Tracking the days of your cycle to work out when you ovulate is otherwise known as the rhythm method. This is the main method used by many fertility apps. Cycle tracking is an important part of understanding your fertility. It is important to know, however, that timing your conception attempts to the rhythm method or fertility apps is only possible if you have a very regular cycle. Ovulation generally occurs 14 days before your period (not on Day 14 as is commonly misunderstood). You need to know when to expect your period so you can work backwards.

The Fertile Window

Remembering the three-day optimal fertile window, look back on your last few cycles and count the days. Day 1 of your cycle is the first day of your menstrual flow (not spotting). The last day of your cycle is the last day before your next flow. If you regularly have a 28 day cycle, ovulation will generally occur at Day 14. Making your fertile window starts at Day 12. Shorter cycles of around 21 days, your ovulation will likely occur at Day 7. Making your fertile window starts at Day 5. Longer cycle of around 35 days, you will generally ovulate on Day 21. Making your fertile window starts at Day 19.

Having said that, it is possible to have a shorter luteal phase (ovulation to menstruation) or irregular cycles, and this can confuse timing. It is common in these instances to have other signs of menstrual function disturbance such as little or no fertile mucus, a variety of premenstrual symptoms including mood changes, tiredness, skin eruptions or cramping, spotting mid-cycle or before your menstrual flow, or period pain. If this is the case, you don’t need to suffer! A qualified and experienced naturopath or Chinese medicine practitioner may assist with herbal medicine, acupuncture or addressing underlying nutritional or lifestyle imbalances to improve cycle regulation, follicular and egg development and hormonal balance.

So whilst the rhythm method or fertility apps can be helpful with regard to timing if your cycle is regular, it can be quite inaccurate if your cycle varies in length. 

2. Know your secretions to know your fertile window

For most of your cycle, your cervix produces a mucus barrier to sperm – almost like a plug, with a thick white mucus that blocks the entry to the womb both physically (as a barrier) and chemically (with immune components that fight foreign materials). We refer to this mucus as ‘infertile’ mucus and it is normal to have this type of mucus at various stages of your cycle (mostly just before and just after your period). As the follicles grow in readiness for ovulation, the balance of hormones produced enable a change in the cervical mucus to facilitate the passage of the sperm towards the egg. The mucus secretions become noticeably wetter and more stretchy and slippery in the days leading up to ovulation, with peak symptoms occurring just before the egg is released. At a microscopic level, the mucus is actually forming channels for the sperm to swim through, as well as providing nourishment for the journey of healthy sperm, and a quality control system to remove damaged or dysfunctional sperm.

Many women also report an increase in libido at this time – more evolutionary genius to further the continuation of the species!

 Where time permits, it is useful to check and record the signs and symptoms of your cycle for a few cycles before you try to conceive. Knowing your signs of ovulation and timing your sex with ease will give you an increased sense of confi dence in your conscious conception and improve your chances of conception.

Checking and recording your cervical mucus changes 

Check your mucus each time you go to the toilet, before urination, by wiping at the opening to your vagina or inserting your finger about 1-2 cm into the vagina and then stretching the mucus out between two fingers. Record the amount, colour, texture and external sensation on your chart. Develop a consistent code that works for you over time to make recording easy and readable. Always record the most fertile mucus (the most wet, watery, slimy, slippery or stretchy mucus) you noticed that day.

  • Your basic infertile pattern of mucus can vary from none/dry or damp, pasty, flaky, crumbly, thick or dense in the non-fertile phases. As ovulation approaches, the mucus pattern will change to creamy or milky and start to become wetter. Your fertile mucus will be clear, wet, watery, slimy, slippery or stretchy at ovulation, more like egg white.
  • How does the outside of your vagina feel? Is it wet or dry, moist or damp? The wetter the sensation, the more fertile you are.
  • The amount of mucus will increase the closer you get to ovulation. Is there a lot of it, a medium amount, or very little?
  • Each woman is different, and mucus can vary from one cycle to another, although generally an obvious pattern will emerge for you. After a couple of cycles are charted, you may start to notice that ovulation generally occurs four days after your mucus changes from your basic infertile pattern to a wetter and more slippery mucus. Or perhaps you have three days of pasty mucus followed by one day of egg white. What is it for you?
  • Immediately after ovulation, there is a marked decrease in mucus production, with a quick return to your basic infertile pattern. You can confirm ovulation has occurred if you are charting your temperature as well (see below), or via a blood test seven days later (the Day 21 progesterone test).
  • Understanding your mucus pattern is the best way to identify approaching ovulation. This helps in getting the timing right for sex and conception. Temperature charting and the rhythm method will only confirm that ovulation has already occurred, and you will miss the fertile window time.
  • It can be very helpful to talk to an expert in fertility charting to understand your mucus pattern.


Infertile Dry No visible mucus.
Ovulation approaching Moist or sticky White or cream-coloured, thick to slightly stretchy. Breaks easily when stretched.
Highly Fertile Slippery, wet, lubricated Increase in amount. Thin, stretchy, watery, transparent, like egg white.
After ovulation infertile Dry or sticky Sharp decrease in amount. Thick, opaque-white or cream-coloured.


It can be difficult to detect cervical mucus after sex due to the presence of semen. Your mucus can also be altered by infection and some medications. When cervical secretions are reduced in quantity or quality it may be associated with:

  • an underlying hormonal imbalance or
  • issues with follicular development,
  • egg quality or
  • health of the cervix.

Thus, it is important to address these issues. Your experienced naturopath or Chinese medicine practitioner will be able to help you here.

When you know your ovulation signs you can ensure that you are getting the timing right. Ensuring you have sex the day or two before and on the day of ovulation when the mucus is at its most fertile. Sex within this fertile window dramatically improves your chances of conceiving compared with untimed frequent sex throughout the cycle. 

3. Test your urine to detect when you may be approaching ovulation

Ovulation Predictor Kits (OPKs) can be useful.  They test for a surge in Luteinising Hormone (LH) – the hormone that initiates the release of the egg. Tracking your mucus changes is usually sufficient to indicate impending ovulation. However, if you want extra information then OPKs are a simple (albeit pricey) test (available online or at a supermarket or chemist). You begin three days before you anticipate your ovulation (i.e. subtract 17 days from your expected menstruation date). Start earlier if you are unsure when this is, or follow the guidelines on your kit. Ovulation usually occurs 24-36 hours after a positive result, so it is ideal to have sex as soon as you see a positive result). It is important to note however, that a positive result does not guarantee ovulation will occur, which leads us to…

4. Chart your temperature to determine when you ovulate

Many women are confused about the value of temperature taking when trying to conceive. There are a lot of arguments for and against charting.  Many medical fertility specialists seem to agree that it is more stressful than useful so best not to bother at all. However, charting your temperature can provide a lot of useful information to someone who knows how to interpret it. Once you have had your unique pattern of temperature explained, it is actually quite easy to understand and can be incredibly empowering!

It is important to take your temperature first thing in the morning with a digital thermometer under the tongue. When we say the first thing, we mean before you talk to your partner, sip on a cup of tea or even move much.  You wake up, roll over and put your thermometer in your mouth and wait until it beeps. 

Usually, there will be a ‘thermal shift’ (temperature increase) of about ½ a degree Celsius that indicates ovulation has occurred. The temperature starts to shift after the egg is released.

The three over five rule 

The three over five rule is where you need to see three mornings of higher temperatures than the last five. This is why you can’t use temperature charts to time your conception attempts.  Once the shift has occurred, ovulation is already over and you have missed your chance. 

You can, however, record any sex you have had and use your chart to see if you did indeed get the timing right in that cycle to know that you are in with a chance.

For more information or to get help on your fertility or pregnancy journey, book in with a Fertile Ground Naturopath