In my last post –The Value of Knowing When you Ovulate, I described how during the menstrual cycle there are noticeable shifts in both Basal Body Temperature and cervical secretions, which give clues to when ovulation occurs. Below I will give some basic guidelines on how to begin to track your cycle to gain valuable information about your overall health and fertility.
These guidelines are going to be most useful for women who are currently having a regular menstrual cycle. If you are not having regular cycles, due to such conditions as amenorrhea or PCOS, or you are breastfeeding, charting your cycle can still be useful but you may need additional guidance from a practitioner. For women in the perimenopause years (i.e. in the lead up to menopause), it is not uncommon for some cycles to be anovulatory (without ovulation), and charting is a useful way to see if this occurs.
As mentioned in the last post, hormonal contraceptives, such as the Pill shut down ovulation and the monthly bleed that occurs is not a true period but a withdrawal bleed, timed by the manufacturers of the Pill to mimic an average menstrual cycle. The synthetic hormones also thicken the cervical fluid to block sperm. This being the case, charting becomes somewhat redundant. It is however, a great tool when coming off Birth Control Pills so that you can see how and when your cycle re-regulates.
Part I: Charting your BBT (Basal Body Temperature)
BBT refers to your temperature first thing in the morning when you wake. Tracking your BBT and cervical fluid (CF) in combination, allows you to determine your ‘fertile window’ (when it is possible to conceive) and confirms ovulation. Your fertile window is approximately 7 days long, 5 days prior to ovulation and 2 days afterwards. This is because an egg can live for 12-24 hours after ovulation, but sperm can live for up to 5 days. (See previous post for more information.)
Start recording your BBT on Day 1 of your cycle, which is the first day of the period when there is a flow of blood. (Pre-menstrual spotting is usually considered the end of your last cycle and is therefore not counted as day 1)
Take your BBT first thing in the morning, on waking. Remain lying down to take your temperature, with minimal movement and before getting out of bed. Also before drinking, eating or doing anything else. The easiest way to do this is to have your digital thermometer on your bedside table where you can easily reach it and put it under your tongue on waking. Then note down your temperature and the time of day on a paper chart, calendar or phone App kept within easy reach.
Your thermometer needs to be digital and show 10ths of a degree, such as this one:
You need to have had 3 consecutive hours of sleep prior to waking to get an accurate reading. Make a note on your chart/calendar if this is not the case, or if you are unwell, have travelled across time zones, or stayed up unusually late. Other things to note are when the clocks change and also alcohol consumption as alcohol can raise your temperature. Noting these things helps to explain any irregularities in your charts when you look back over them at a later date.
Try to take your temperature at approximately the same time every morning, and make a note of any significant variation. Your temperature tends to rise about 2/10ths of a degree per hour, the later you wake.
During the follicular phase (before ovulation), your temperatures will typically be lower and range between 36.1 – 36.5 degrees Celsius / 97.0 – 97.7 degrees Fahrenheit. You may have high temperatures during your period due to the residual effects of progesterone from the last cycle but these should then lower for the remainder of the follicular phase. (Please read my last post for more information about the different phases of the menstrual cycle).
* If your temperature is repeatedly below 36.1 degrees C. consider getting your thyroid checked by your doctor because this could be an indicator of an underactive thyroid.
On the day of ovulation itself, typically the temperatures will dip slightly, which you may or may not record, depending on the time of day ovulation occurs in relation to when you take your temperature. You may also notice a pea-sized lump under the skin on one side of your groin, the right side correlating to ovulation from the right ovary and the left groin correlating to ovulation from the left ovary.
Post-ovulation, due to the rise of heat-inducing progesterone, your BBT should increase by 0.4 – 1.0 degrees to around 36.5 degrees C. / 97.8 degrees F. or higher, ideally to 36.7+ degrees C. / 98+ degrees F. This rise should occur within 1 – 4 days, ideally within 1-2 days of ovulation and then stay raised. If you became pregnant, your BBT will remain high beyond when you would next expect to have a period. If you are not pregnant, a day or so before your next period, your BBT will drop due to the drop in progesterone that signals the womb lining to shed.
You will need to chart for three to four months before being able to reliably know when you are ovulating but what you should begin to notice is that your temperatures pre-ovulation are in the lower range, and then (if you are ovulating) that there is a distinct shift in temperature post-ovulation. When you have charted for a few months you can also count back from your period to when your chart suggests you are ovulating and get a sense of the length of your luteal phase. This then works in the other direction so that when you see that you have ovulated, you can more accurately predict when your next period will be.
(Photo credit: www.julesbogdanski.com)
A word on Apps:
Although there are some increasingly good Apps out there for charting, please note that many have ‘predictive’ functions, which may give false readings for your individual cycle. A paper chart is a good place to start at least for the first few months, and/or you can see if you can turn off the predictive function on the App.
Part II: Charting Your Cervical Fluid (Also known as cervical mucus)
There are different types of cervical fluid (CF) produced at different times of the month by the cervix. The cervix is the lower, narrower part of the womb that connects the womb to the vagina/birth canal. It is approximately 25 mm long and contains several hundred crypts (glands) lined by cells, which manufacture this fluid. Different crypts produce different types of CF at different times in the cycle.
So lets look at the changes in CF that you may see during a healthy menstrual cycle:
After menstruation ends, typically there can be a few dry days when no CF is noticed depending on the length of the period in relation to the length of the follicular phase overall. Then as you approach ovulation you will likely start to notice CF, either in your underwear, in the shower, or when you wipe when going to the bathroom. You can also check with a clean finger at the opening of the vagina, before urinating. (You do not need to go further inside the vagina to check as this could give a false reading.)
The typical changes that occur with the fluid during the cycle follow this general pattern: (Menstruation) – Dry – Sticky/paste-like – Creamy – Egg White / Wet (Ovulation) – Dry – (Menstruation)
You may start to develop the wetter quality cervical fluid as early as 4 to 7 days prior to when ovulation actually happens. It is also possible that you may only notice it for a day or two beforehand.
This wet, slippery fluid is known as ‘Fertile’ CF and when seen under a microscope, has vertical channels to aid the sperm’s journey to the egg! Other types of CF appear crosshatched under a microscope, which works to block the sperm.
Typically, the peak day of wet CF (when it is most profuse) is the day before, or the day of ovulation.
Post ovulation CF becomes dryer again with the predominance of progesterone, until the next cycle begins with menstruation. You might however notice a slight surge of creamy CF half way through the luteal phase, which coincides with a corresponding surge of oestrogen.
*If you have never noticed any CF and are not on hormonal contraceptives, don’t panic! Begin with an intention to look out for it, especially around the middle of your cycle. If you still don’t notice anything, there are things you can do dietary-wise to support cervical fluid production. Also, be aware that soaps and perfumed products can disrupt the delicate PH of the vagina so being mindful of the products you are using can also help.
Here is an interesting extract from ‘The Discovery of Different Types of Cervical Mucus and the Billings Ovulation Method’, by Erik Odeblad: Odeblad_Discovery of Cervical Mucus_1994.pdf
“The principal indication of fertile days in a menstrual cycle is the appearance and the sensation of a wet substance emanating from the epithelial membrane of the cervix. This sign precedes ovulation and depends upon the growth in the ovary of a follicle, which produces oestrogens and which is usually succeeded by the rupture and the release of an ovum (ovulation). The last day on which this substance with fertile characteristics is observed is called the Peak day. This day is also the day of ovulation in 80% of cycles. Ovulation occurs on the preceding day in about 10% of cycles and in about 10% of cycles on the day following the Peak.”
As you can see from my guidelines above, CF shows us that ovulation is approaching and after several cycles of charting you will get a sense of how many days of CF you typically see. It is the temperature shift however that confirms ovulation has occurred, so charting both CF and BBT together is recommended to accurately assess your ‘fertile window’. When done correctly, fertility awareness is 99.6%1 effective as a method of contraception. However in order to do it correctly, you MUST first get to know your cycle inside out and chart for at least 3 months. If your cycle is irregular you will need to take extra precautions to avoid an unwanted pregnancy, or work with a practitioner trained in cycle charting.
Cycle charting for conception:
If you are wanting to conceive remember your ‘fertile window’ can start as early as 5 days before ovulation due to the potential life span of sperm, as long as there is slippery/wet CF present. An egg can then survive and be fertilised for 12-24 hours after ovulation, so aim to include those days too. Trying to conceive every other day during the fertile window, including the day of ovulation is a good rule of thumb.
Cycle charting for contraception:
If you are not wanting to conceive, you will need to take extra precautions from at least 6 days before your ovulation is expected to occur, or earlier if you notice any ‘fertile’ CF. You will then need to continue to use additional non-hormonal contraception until you have seen 3 consecutive higher temperatures, following the post-ovulatory temperature rise. After this time your fertile window has ended. (Please be mindful of unusual factors that also cause a temperature rise, such as a fever).
*Outside of your fertile window you cannot get pregnant due to the absence of the fertile CF and or/the lifespan of the sperm and egg. However there is something called your ‘lunar return’, when both women and men are said to have heightened fertility. This is the day when the moon is in the same phase as it was on the day you were born. So for example, if were born on a full moon, then you can have heightened fertility on the full moon in any given month. You can look this up online.
Please remember that until you have charted for several months and you are clear of your own patterns, it is recommended to use other forms of non-hormonal contraceptives, such as condoms.
What does a chart look like?:
In terms of charts, you can use something as simple as a month-to-view calendar and just keep a written record of your BBT, time taken and any noticeable symptoms. Or, there are charts online that you can download that allow you to plot the temperature graph and keep track of other symptoms with greater detail, such as is available here: http://www.nfpta.org.uk/charts/ . The key is finding something that feels simple and doable for you.
Image: Red and Black Calendars
As a final note, when trying to conceive sometimes charting the cycle can become an additional source of stress, which is counterproductive. If it is not working for you and stresses you out, please take a break from charting and just follow your instincts. That said if you have never tried charting, I invite you to give it a go and start to uncover the patterns of your own unique cycle. Understanding your cycle gives many insights above and beyond aiding conception or as a method of contraception.
The above is really only the tip of the iceberg in terms of the depth of information a chart can convey but I wanted to provide a starting point. If you’d like to learn more, a classic book to read is Toni Weschler’s Taking Charge of Your Fertility: The Definitive Guide to Natural Birth Control, Pregnancy Achievement and Reproductive Health and there are also online courses and trained practitioners, who specialise in decoding charts.
- Hannah Ransom: http://herfertility.com/join-free/
Visit our Women’s Health Page for more information about the treatments we offer to help support your cycle and fertility.
You can read more blog posts about fertility here.
