Understanding your Menstrual Cycle, and the best ways to track your cycle.
Whether you’re trying to conceive, trying to prevent pregnancy, or just trying to get a better idea of your hormones and menstrual cycles, tracking your cycle can be helpful. Cycle tracking can also be helpful for giving you some more information to identify whether you ovulated during your cycle or not, even when having regular periods. Knowing this information can also help you to know how different aspects of your lifestyle may be impacting your cycle.
Understanding your Menstrual Cycle
The average menstrual cycle is 23-29 days, but it’s still considered ‘normal’ if its anywhere between 21-35 days – shorter or longer than this would be considered an irregular cycle. Ideally, we want cycles to be between 24-32 days if were talking ‘optimal’. Your cycle may also change and have some variation, of around 3, or even up to 9 day differences between cycles and over the years, and it can still be considered normal – but there shouldn’t be more than 20 days in difference between cycle lengths month to month or over the year.
In a ‘normal’ menstrual cycle, there are 4 different phases. These phases allow for hormonal and physical changes which helps your body to produce an egg and prepare the uterus for pregnancy (whether that’s your goal or not).
The 4 phases of your menstrual cycle are:
1. Menstrual – this is when you have your period, and its part of the follicular phase of your cycle. The first day of your cycle is the first day of your period!
During the menstrual phase, estrogen and progesterone hormones are low, and the lining of the uterus (called the endometrium) is shed, which results in the bleeding you experience.
2. Follicular – the follicular phase is roughly the first 14 days of your cycle if you have a 28 day cycle. It starts on the first day of menstruation, and ends with ovulation.
During the follicular phase, follicle stimulating hormone (FSH) is released, which stimulates the ovary to produce 5-10 follicles, which bead on the surface of the ovary. The growth of these follicles stimulates the uterine lining to thicken in preparation for a possible pregnancy, and the levels of estrogen and progesterone start to increase.
3. Ovulatory – if you have a 28 day cycle, ovulation typically occurs around day 15-17, but there can be a bit of variation based on your cycle length. Typically, ovulation should be happening around 14 days before the start of your next period, but a normal luteal phase can be anywhere from 11-17 days, so the exact timing of ovulation can vary a little bit from person to person, and cycle to cycle.
The rising levels of estrogen triggered during the follicular phase cause the release of a hormone called gonadotropin-releasing hormone (GnRH), which then prompts the release of Luteinising Hormone (LH) and FSH. The release of these hormones is what triggers ovulation to occur. During ovulation, the egg bursts from the follicle, but the ruptured follicle will still remain on the surface of the ovary.
4. Luteal – The luteal phase follows ovulation and is the remainder of your cycle until your next period begins. Typically days 17-28 or so.
Over the ~2 weeks after the release of the egg during ovulation, the ruptured follicle that remained on the follicle transforms into a structure called the corpus luteum. This structure starts to release progesterone, and small amounts of estrogen. The combination of these hormones maintains the thickened lining of the uterus, as it waits for a fertilized egg to implant. If no fertilization happens, the corpus luteum will die (typically around day 22 in a 28 day cycle) and progesterone levels will drop, which triggers menstruation to begin and the cycle then starts over.
Cycle Tracking
There are several different methods to track your cycle, including charting by:
- Calendar
- Mood
- Cervical Fluid + Position
- Hormones
- Temperature
Calendar tracking is likely what you’re most familiar with – this is simply using paper and pen, or an app, to track the start date of each cycle. This gives you the length of the cycle, and you can then estimate ovulation based on cycle length – the assumption is that the luteal phase is 14 days, but it can range from ~10-17 days, so we can subtract that amount from the total cycle length to get an estimated day of ovulation.
Calendar tracking is unlikely to be accurate to the day for ovulation, especially if your cycle length varies, but it can be helpful in addition to other tracking methods.
Mood tracking means noting mood changes across the cycle. This isn’t reliable on its own, but some people will find more noticeable changes based on what point of their cycle they’re at, and so can again be a helpful addition. Measuring sex drive is probably the most useful mood to track and tends to increase leading up to ovulation, but it’s not always aligned with ovulation.
Cervical Mucus has pretty good evidence, but again not reliable on its own, more so as additional data. Cervical fluid or mucus tends to be more watery, slippery, stretchy, clear, and have an egg white consistency in the days leading up to and including the day of ovulation. In the days following ovulation, cervical mucus may change to a creamier consistency, decrease, or dry up.
Cervical Position includes measuring height, softness, and opening. Height has very little science, but involves measuring (with a finger) the height of your cervix from the opening – closer to ovulation the cervix may be higher up. The cervix may also be softer (think the softness of pushing on lips vs pushing on your nose or chin) prior to ovulation, and the cervix tends to have a wider opening. The cervix is typically mostly closed to prevent infection – it will only open during menstruation, then open again during ovulation, and close again following (this is why some experience spotting around the time of ovulation, as the cervix opens up and anything that may have been remaining from the last period can come out.
Hormone tracking includes bloodwork from your doctor, but for at home tracking would typically be through using an ovulation predictor kit (OPK). OPK’s measure LH alone, or LH and estrogen. Some kits will also include progesterone test kits.
When testing only LH, you’re typically only seeing the peak about 12-24 hours prior to ovulation. This can be helpful for predicting ovulation, but you may be missing the wider fertile window which is around 3 days leading up to ovulation, so LH alone may result in you not being aware of the full fertile window.
By tracking estrogen as well, you can have a better idea that the fertile window has begun, as it increases closer to the start of that window.
Progesterone spikes about 7 days following ovulation, so testing at home or at the lab can confirm that ovulation has occurred. Often this will be tested on cycle day 21, but if you’re cycle is not 28 days, then it would need to be adjusted to be 7 days following ovulation.
Temperature tracking can be done using a Basal Body Temperature thermometer (BBT) or by a wearable device like an Ava Bracelet, OvuSense or TempDrop. If using a BBT, your temperature has to be checked everyday at the same time, before getting up out of bed in the morning. The wearable devices are typically more convenient as they track your temperature overnight, but also come with an added cost.
Temperature tracking is helpful for confirming ovulation occurred after the fact, as it will show the slight temperature change that occurs following ovulation. You need atleast 7 days of continuous tracking to get a good idea, but ideally you should be measuring your BBT daily throughout your cycle. Following ovulation, body temperatures tend to increase slightly (about 0.5-1.0°F, or 0.3-0.6°C). Sometimes there may be a slight dip in temperature just before ovulation, but this is less reliable.
I personally find a wearable device much easier than having to test with a thermometer everyday - I use TempDrop as a wearable BBT device, and have an an affiliate discount - use this link to get a coupon for 10% off! http://tempdrop.refr.cc/rachelhiltsnutrition (this coupon can be combined with other sales!).
What’s the best method for tracking your cycle?
The most accurate method for at home cycle tracking is usually a combination of hormones and temperature tracking. I recommend trying out a few different methods on different cycles, and see what you prefer.
I find that once you’ve tested hormones for a few cycles and have gotten a feel for your cycle, most women do well just tracking temperature and cervical mucous.
A combination of methods can be the most effective, but it’s also important to keep in mind the financial and emotional costs, so find what works best for you.
Just because you measure one cycle and see you ovulate on X day, doesn’t mean this will be the same with every cycle, so try to pay attention to trends over several cycles to help you get to know what signs to watch for with your own body and cycle.
Cycle tracking is a helpful way to gain some more information about your cycle, especially if you are trying to conceive, or trying to prevent pregnancy and are not using birth control. If you are on hormonal birth control, of course you won’t be ovulating and so tracking this information would not be as useful.
Tracking all this information on a paper chart or within an app can help to keep it all straight! Some chart options include through Ava, Fertility Friend, or many others available for free or a fee.
References:
1. Rosetta L, Thalabard JC, Tanniou J, Ducot B, Maitrot-Mantelet L, Rousset-Jablonski C, et al. Ovulatory status and menstrual cycle duration assessed by self-collection of urine on pH strips in a population-based sample of French women not using hormonal contraception. Eur J Contracept Reprod Health Care. 2017;22(6):450-8.
2. 2. Mihm M, Gangooly S, Muttukrishna S. The normal menstrual cycle in women. Anim Reprod Sci. 2011;124(3-4):229-36.
3. Reed BG, Carr BR. The Normal Menstrual Cycle and the Control of Ovulation. In: Feingold KR, Anawalt B, Boyce A, Chrousos G, de Herder WW, Dungan K, et al., editors. Endotext. South Dartmouth (MA): MDText.com, Inc.
