It’s time to go back to the basics when it comes to periods. Enter: cycle tracking. The term itself sounds daunting and complicated, but the practice is ancient and can actually be pretty interesting and super empowering once you get the hang of it. Tracking abounds with benefits: body awareness, identifying potential hormonal imbalances, PMS symptom management, and increased libido-–not bad, eh? Why don’t they teach this stuff in school?
While we’ve certainly come a long way from depending upon the moon, up until just a few years ago, ovulators had to create their own graphs in order to accurately track. But these days, it’s easier than ever to help you ditch that graphing paper thanks to awesome tools like Daysy, an intelligent fertility tracking device that incorporates a smart thermometer and a cycle-tracking app!
But wait, isn’t cycle-tracking, like, religious, and not based in science?
No! Common misconception. There are different methods of tracking one’s cycle. And, while all rely on the ovulator’s knowledge of their own menstrual cycle and signs of fertility (fuck ya!), The Fertility Awareness Method (or, FAM for short) is entirely based in science (it uses multiple factors like cervical fluid changes, temperature changes and cervical position to help you learn your individual cycle) and is not associated with religion at all. Instead, FAM is the secular version and Natural Family Planning, the religious version! The difference is that during fertile days, an ovulator who wanted to avoid pregnancy and was practicing NFP would choose to abstain from sex for religious reasons whereas with FAM, an ovulator might defer to barrier methods (i.e. condoms) to prevent pregnancy (5). The conclusion; FAM is not the same as Natural Family Planning!
What more is there to understand about my cycle outside of my period?
There’s actually so much that happens in an ovulator’s body during the menstrual cycle outside of the bleeding phase (aka getting your period). For one, you actually have four distinct phases that occur within the menstrual cycle if you are not on hormonal birth control (who knew?!): follicular, ovulatory, luteal, and menstrual (this is technically part of the follicular phase, but we like to put it in its own category because menstruation is certainly distinct from the rest of the cycle!) and five hormones that manage it all: estrogen, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone.
We told you––a lot is happening.
Let’s break it down:
Phase 1: Menstrual
- Duration: 3-7 days
- When: If an egg doesn’t get fertilized.
- What: The unfertilized egg gets reabsorbed into the body (no, it doesn’t become a new egg!) causing the level of the hormone progesterone to drop. This progesterone drop signals the lining of the uterus to shed since it isn’t needed to support a pregnancy (3). (The lining was built up earlier in the cycle to support implantation if the egg were it to get fertilized- more on that later…)That shedding = menstruation (plus some blood and mucus in there too- yum! (2))
Phase 2: Follicular
- Duration: approx. 7-10 days. This is the phase that has the most variation from cycle to cycle within an individual. Meaning, if your total cycle length is inconsistent, it is usually this phase that varies in length from cycle to cycle.
- When: The first day of menstruation through ovulation.
- What: Inside the ovaries are teeeeeeny tiiiny immature follicles (you have about 400,000 of them at puberty!). These small fluid sacs each contain an immature egg. During the follicular phase, the hypothalamus, that small (but mighty important) center area in your brain, signals to the pituitary gland to release follicle-stimulating hormone (aka FSH) to your ovaries (3). This FSH kick causes some of these follicles to swell and begin to develop. All the while, these follicles are producing estrogen to help thicken your uterine lining in preparation for implantation. This is known as the “estrogen-dominant” part of the cycle- because, well, estrogen is dominating!
Phase 3: Ovulatory
- Duration: 3-4 days
- When: Not always on day 14! Tracking your cycle with a tool like Daysy, as well as checking your cervical fluid (more on that here!), can actually help you identify when you’ve ovulated. It’s also important to know that while the ovulation phase is 3-4 days, the fertile window is actually usually more like 6 days! This is the lifespan of egg plus lifespan of sperm.
- What: FSH is increasing, but now your luteinizing hormone (LH) steps in, too. This hormonal blast causes one follicle to further swell until POP! It bursts and releases its now mature egg into the fallopian tube and begins to make its way to the uterus (3). If a sperm is able to reach it, it has about 24 hours to make some magic. Testosterone also takes a quick surge (to boost your sex drive!) (3).
Phase 4: Luteal
- Duration: approx. 12-16 days. This generally stays consistent, within a day or two (7), for each individuals’ cycles. Meaning, it would be unusual for your luteal phase to be 12 days on one cycle, 16 another, and then 14 the next. Variation in your overall cycle length is usually due to variation in your follicular phase.
- When: Post-ovulation until you start bleeding again.
- What: You know the follicle that cannonballed your egg into your tubes? Well, it doesn’t just go to waste, it has another job! It transforms into a corpus luteum (a fancy word for a mass of cells that forms in your ovary) (10), which produces the hormone progesterone. Progesterone takes over at this point to help keep your uterine lining intact (3). Why? Well, if that egg were to become fertilized, it needs a safe and cozy home to implant itself in to grow. By keeping the uterine lining intact, progesterone is helping to keep the egg warm and toasty in your uterus. You have now entered the, you guessed it, progesterone-dominant phase. This uptick in progesterone tells the body to stop sending out FSH and LH so that no more eggs are released in an untimely manner. If the egg hasn’t been fertilized, the corpus luteum is reabsorbed into the body, halting progesterone production. Remember what this means? You’ll be shedding that lining. We’re back at the beginning! Or the end? It’s called a “cycle” for a reason!
Where do I start with cycle tracking?
With our busy modern lives, the thought of tracking your cycle can seem unappealing, to say the least. You must be thinking: another thing to add to my to-do list? But thanks to companies like Daysy, we luckily don’t need to rely on the moon to figure out when our period is coming.
So how does Daysy work? Upon waking and before doing anything else (hold that pee!), you measure your temperature with the Daysy thermometer. Remember how that progesterone heats up the uterus? Well, it also causes your entire body temp to rise! In fact, once you’ve ovulated, your temperature increases by 0.25-0.45 degrees Celsius (6), and that temperature shift indicates a shift in your cycle phase (hello progesterone-dominant phase!). Then there’s just one more thing you need to do; enter in when you’re on your period! With this information, using a sophisticated algorithm which has been developed over 34 years, evaluated over 10 million cycles, and is backed by scientific research, Daysy calculates your fertile window for you, conveying it simply and clearly through lights! Red means fertile, green, infertile, and yellow that Daysy is becoming better acquainted with you or that your cycle is fluctuating. How much easier can that get?
We had Qs for Daysy. Their team answered!
What happens if your temperature doesn’t shift?
If the Daysy user does not experience the temperature shift indicating ovulation, Daysy’s lights will stay red, indicating the fertile window is still open and will remain open until ovulation is confirmed. Many people experience the occasional monophasic (no temp shift occurs) or anovulatory cycle (when ovulation doesn’t occur), but if this happens often, you should contact your healthcare provider for insight into the root cause.
How does cervical fluid play into the equation?
Daysy is designed to be easily usable, without requiring specialized training and a thorough understanding of cervical mucus or the fine details of cycle analysis. Daysy was created to be straightforward and reliably applicable.
While we do encourage our users that are planning a pregnancy to observe cervical mucus in combination with basal body temperature to further narrow down the fertile days, we do not encourage limiting infertile days and giving yourself extra “greens” based on cervical mucus observations, when you are not yet ready for a baby. However, the DaysyView app includes an optional tool to track the different kinds of cervical fluid easily and simply, if you wish to do so.
What makes your thermometer special?
The Daysy sensor is a unique and highly calibrated basal body temperature thermometer that can measure the shift in temperature that indicates ovulation. The Daysy sensor is unlike many other basal body temperature thermometers in that it tracks the stabilized basal body temperature and does not average out the data received while the temperature is being recorded. What this means is that Daysy waits for the basal body temperature to stabilize to get the most accurate reading. Other basal body temperature thermometers will take a number of readings over a short period and merely average out the values to get one end value. This is how some basal body temperature thermometers can be very fast. Waiting for the actual, stabilized basal body temperature means Daysy is getting the real temperature value and not just a prediction or average.
Any other cool facts/features of the app?
Daysy is a device that learns your unique cycle – hence, there is an initial 3 cycle learning phase and the existence of the yellow light to indicate your cycle fluctuations. Daysy actively learns and adjusts calculations to your individual cycle, each cycle.
Written by: Kristina Samulewski
All content found on this Website, including: text, images, audio, or other formats, was created for informational purposes only. The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
(1) “What Cycle Tracking Can Tell You About Your Health.” UNC Health Talk. April 24, 2019. https://healthtalk.unchealthcare.org/what-cycle-tracking-can-tell-you-about-your-health/
(2) Department of Health & Human Services. “Menstrual Cycle.” Better Health Channel. April 30, 2014. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/menstrual-cycle
(3) Vitti, Alisa. Woman Code: Perfect Your Cycle, Ampilfy Your Fertility, Supercharge Your Sex Drive, and Become a Power Source. New York, NY: HarperOne, an Imprint of HarperCollinsPublishers, 2014.
(4) Vitti, Alisa. “The Potential Harms of Synthetic Birth Control.” Well+Good. February 26, 2018. https://www.wellandgood.com/good-advice/health-risks-synthetic-birth-control/
(5) Welch, Claudia. Balance Your Hormones, Balance Your Life: Achieving Optimal Health and Wellness through Ayurveda, Chinese Medicine, and Western Science. Cambridge, MA: Da Capo Lifelong, 2011.
(6) Valley Electronics. “Technology.” This Is How Daysy Works – Natural Ovulation Tracking. https://usa.daysy.me/technology/
(7) App, Official TCOYF. “Fertility Info.” Taking Charge of Your Fertility. October 23, 2017. https://www.tcoyf.com/fertility-info/
(8) Dean-Jones, Lesley. “Menstrual Bleeding According to the Hippocratics and Aristotle.” Transactions of the American Philological Association (1974-) 119 (1989): 177-91. doi:10.2307/284268.
(9) “What Are Follicles And Why Are They Important For My Fertility?” London Women’s Clinic.https://www.londonwomensclinic.com/what-are-follicles-and-why-are-they-important-for-my-fertility/
(10) CRNP, Lori Smith BSN MSN. “Corpus Luteum: Function, Formation, and Cysts.” Medical News Today. December 26, 2017. https://www.medicalnewstoday.com/articles/320433.php