What is an irregular cycle anyway?
There are three areas that influence whether a cycle is irregular or not. These are: overall cycle length, blood quantity and quality, and whether you’ve ovulated. It’s possible for your cycle to be affected in all of these areas, two of these areas, or just one of these areas.
Sources vary on what is considered a healthy cycle length. The US Dept. of Health and Human Services’ Office on Women’s Health, marks an irregular cycle by “either shorter than 21 days or longer than 35 days” (1). The International Federation of Gynecology and Obstetrics deem a cycle length of 24 to 38 days to be within “normal” range (2).
So, right off the bat we are reminded that “normal” looks different for everybody! And, that we certainly should not all be assuming that our cycles are 28 days! In fact, a 2019 study reported that only 13% of 600,000+ cycles studied were 28 days long, and that the average cycle length was actually 29.3 days (5). Pshhhh!
It’s also important to remember that your cycle isn’t fixed. There are so many factors that affect the menstrual cycle so it is very possible for your own cycle to change in length from month-to-month (e.g. 22 days one cycle, then stretch out to 33 the next) (1).
Do you know how long your cycle is? While many of us know how many days we bleed (it’s kinda hard not to notice!) most of us don’t know how long our full cycles actually are. This is where cycle-tracking becomes super handy. And, you don’t have to do it on your own! Daysy is a super handy fertility device that makes figuring out how long your cycle is super easy. Like, 60 seconds a day easy! Daysy uses an advanced temperature sensor along with an intelligent algorithm (based on scientific evidence and over five million cycles) to give you personalized info about your cycle. Woah! And all you need to do is take your temperature each morning, plug in your period info, and voila!
What’s more, if you sync your Daysy with their app, Daysyview, you can get a breakdown of your average cycle length from your historical data.
And why is this important? Cycle-length is determined by hormone ratios. So if you are experiencing great variation in cycle-length from cycle to cycle, or you learn your cycle is super short or super long, it may be a clue that you need to support your hormones. And, if you are trying to get pregnant, or avoid pregnancy, knowing that your cycle length changes is vital to staying on top of your unique fertile window (which can also change slightly from cycle to cycle).
Important note: Daysy is only recommended for those with cycles 19-40 days in length. That includes a lot of people who see themselves as having irregular cycles!
In addition to cycle length, an irregular cycle can be characterized by how much, or how little, you bleed. Heavy bleeding, or menorrhagia, is defined as bleeding more than seven days during your period and/or soaking through one (or more) menstrual products in an hour (3). While this isn’t super dangerous on its own, menorrhagia can cause anemia (3,4) and it is a good reason to check in with a practitioner so that you can get some support!
It is also possible to bleed too little during your period. If you notice you are only spotting, and/or your period is less than 3 days, this is also a good indication to check in with a practitioner for some support.
Lack of Ovulation
In a healthy, pre-perimenopausal menstrual cycle, ovulation (aka, an egg being released from a follicle in the ovary) occurs each cycle. It is possible, however, during an irregular period, for ovulation not to occur. This is called an anovulatory cycle. And, because you can still bleed even if you didn’t ovulate, it can be hard to tell if this is happening to you. Luckily, ovulation can be detected by a rise in your basal body temperature (BBT). Tracking your temps regularly can help you recognize whether or not you are ovulating (more on that HERE). How does one do that, you ask? Here is where a tool like Daysy comes back into play! Daysy measures and tracks your temps for you and gives you your fertility status for 24 hours based on current and past data, using it’s special algorithm. Cool! So, basically, if you aren’t ovulating, the info Daysy provides may be able to alert you to this! #grateful.
What causes a true irregular cycle?
Before we dive into the cause of irregular cycles, we reco you get a little refresher on how the hormones in the menstrual cycle work HERE and HERE. As a reminder, hormones are substances produced by the body that act as chemical transmitters or messengers. AKA they tell your body what to do! The menstrual cycle is a highly coordinated series of events involving interactions between lots of different hormones (almost like a dance routine!) So, hormones getting “out of sync,” is often the cause of menstrual irregularities.
There are two “camps” of cycle-disruptors: medical conditions and lifestyle.
Medical conditions that can cause irregular cycles
Please note, we are not diagnosing here! Rather, we want to give you a starting point to be able to have a more informed convo with your practitioner, if in need!
Polycystic Ovary Syndrome (PCOS)
All bodies produce androgen hormones (the group of hormones typically associated with those assigned-male-at-birth, like testosterone) in varying amounts. In fact, testosterone is a key hormone in the menstrual cycle! But, those with PCOS make higher levels of androgen hormones, which then prevents the other cycle-hormones, like estrogen and progesterone, from functioning as they typically would in the menstrual cycle. (6) This can lead to anovulation (6) as well as cyst-like appearances in the ovaries (6,9).
According to the The National Library of Medicine, PCOS affects up to 21% of menstruating people (9). Its root cause is not entirely understood, though there is evidence to suggest it’s hereditary, and there is a documented link between insulin resistance and PCOS (10,11).
Other symptoms to look out for
Acne, hair growth (usually on the face, chest, or lower abdomen), and weight gain (9).
Sound like you? Your practitioner can help diagnose you.
The thyroid is a spongy, butterfly-shaped gland located in the neck. Its job is to secrete hormones that assist with growth, development, and metabolism (13). So by now, we know you know, that hormone secretion from the thyroid impacts the menstrual cycle as well.
There are two major kinds of thyroid dysfunction: an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism).
People with hypothyroidism have thyroids that either don’t produce enough hormones or don’t respond properly to hormones (13). For menstruators, this can result in irregular cycles, heavy periods, and infertility.
People with hyperthyroidism produce higher-than-typical levels of hormones. For people with menstrual cycles, this can result in amenorrhea, or the absence of menstruation (13).
Other symptoms to look out for (just to name a few)
Hypothyroidism = fatigue, constipation, dry skin, increased sensitivity to cold
Hyperthyroidism = excessive sweating, heat intolerance, weight loss, diarrhea or loose stools.
How do you know if you are experiencing thyroid dysfunction?
Well, tracking your cycle could help because low BBT can indicate thyroid issues. By precisely measuring your BBT, Daysy can give you the information that might indicate a potential thyroid issue. As always though, if you’re concerned, head on over to your practitioner’s office to hand that data over and for any tests (like blood work!)
Fibroids are lumpy growths that can pop up on or inside the uterus (15). Although these bumpy beauties are not cancerous, they can cause pain and mess with your cycle (15). People with fibroids might experience menorrhagia, or they might experience spotting in between periods. Roughly 30% of vagina-bearing people over 30 have fibroids (16).
Other symptoms to look out for (to name a few)
Increased menstrual cramping, pain the pelvis or lower back, increased urination.
Your medical practitioner can usually detect uterine fibroids during a pelvic exam, and use a variety of imaging techniques to verify (15).
Primary Ovarian Insufficiency (POI)
Sometimes referred to as premature ovarian failure (POF), the Mayo Clinic defines POI as a condition that “occurs when the ovaries stop functioning normally before age 40” (20).
POI is not the same thing as premature menopause. While people who go through premature menopause stop having periods completely (and therefore are incapable of becoming pregnant), people with POI sometimes have periods and between 5-10% of them can carry a pregnancy to term (20).
Those who have POI experience skipped periods. If you have missed your period for three months in a row and are not pregnant, talk to your practitioner!
Other symptoms to look out for (to name a few):
Infertility, vaginal dryness, lowered sex drive, hot flashes, and night sweats (20).
Real quick: even though we are grouping perimenopause under the “conditions” category, it is not a “medical condition” to be “fixed.” Perimenopause is a stage that all menstruating people go through as their bodies gear up for menopause. This can begin at different ages for different people. Over the course of this 5-10 year period, ovary-bearing people’s bodies undergo a set of hormonal changes that cause menstrual irregularities (21).
So, just to reiterate: perimenopause = not something that needs to be treated! Just a good thing to know if you are experiencing wacky cycles and getting older 🙂
So, you don’t have any of the conditions described above, but still have irregular cycles? Menstrual probs? Remember, anything that affects your hormones can mess with your cycle.
Here’s a brief (but by no means exhaustive) list of lifestyle factors that can affect your hormones.
You know the good ole fight-or-flight response? When you have an impending deadline or tricky traffic situation, or just plain ole life stressors, your body is going to halt production of any non-immediately-necessary hormones and favor those that can help you get the hell outta the way from what is spiking those stress levels in the first place… so you can fight, or flight. Reproductive hormones get categorized as “nix for now” (23). Hence, menstrual irregularities.
What to do:
Meditation and/or other mindfulness activities, exercise, engaging in solo or partnered sexual activity (24,25,26)
Zzzzs, or lack thereof, can impact your reproductive hormone levels—and thus your menstrual cycle. One literature review surmised that vagina-bearing people with abnormal sleep schedules (e.g. shift workers) were more likely to have irregular menstrual cycles (27). Check out this whole piece on how sleep can impact the cycle!
What to do:
Prioritize rest! Try resetting your sleep schedule according to these guidelines from the National Sleep Foundation. If your work or school schedule means you can’t change your sleep sched, then try squeezing in high quality sleep when possible.
Dietary and Weight Changes
Taking in more or fewer calories than usual, as well as eating a vegan or vegetarian diet can all lead to variations in your cycle (28,29).
Why? Adipose tissue, which serves as your body’s fat stores, has a close relationship with the hormone estrogen. If the amount of adipose tissue in your body increases, that can cause your body to make more estrogen leading to a hormonal imbalance leading to, you guessed it, an irregular cycle. (30). Conversely, not enough fat and nutrients may cause missed periods and / or shorter periods.
If you have experienced weight loss, sometimes the body reads this as stress. The way your hormones may respond echoes something similar to fight-or-flight where your body goes into conservation mode, focusing on making the “immediately necessary” hormones and potentially preventing menstruating (28).
What to do:
Remember to eat a balanced diet with lots of real, whole foods.
If you are missing periods or only spotting, and you are open to eating animal foods, see what happens if you reintroduce some well-sourced animal proteins. If you don’t eat animal foods, see if you can find supplements for the missing iron, and vitamins, and eat healthy fats like avocado, olives, and coconut.
There are also many practitioners that use dietary changes to help you make your period better!
While we are so often taught the importance of movin’ and groovin’, it is also possible to overexercise. Overexercise (especially in conjunction with a restrictive diet) can induce your body’s stress response and, yes, mess with your cycle (31). Too much exercise can also lead to being underweight or losing weight which we mention the effects of above.
What to do:
Try softer movement practices on some days like gentle yoga (hatha or restorative. Not hot yoga, vinyasa or flow!)
Certain medications’ side effects include changes to the menstrual cycle. Here’s a shortlist from the University of Michigan Health System of cycle-impacting meds:
- Aspirin and other medicines (called blood thinners) that prevent blood clots.
- Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (for example, Advil or Motrin) and naproxen (for example, Aleve).
- Hormonal forms of birth control, such as birth control pills, Depo-Provera injections, Nexplanon implant, and the levonorgestrel IUD (Mirena, Liletta, Kyleena and Skyla).
- Hormone therapy.
- Medicines used to treat cancer (chemotherapy).
- Thyroid medicines” (33).
If you are taking one (or more) of these medications and notice changes to your cycle, talk to your healthcare provider! Also note, if you are using Daysy to track, some medications are not compatible as they impact BBT readings. If you have questions, contact the Daysy customer support and their medical advisor will assess your situation.
The Long and Short of It
There is no such thing as the “perfect” cycle! Every menstruating person’s cycle is unique and constantly changing, thanks to the constant flux of hormones that keep us going.
But, it is possible to have an “irregular” cycle. And an irregular cycle shows us that something is up with our hormones and some support might be useful. One of the most useful ways to know if you have an irregular cycle? Tracking, baby! And while, sure, you can use good ole graph paper, a pen and a BBT thermometer to do so, Daysy does the hard work for you and has the added benefit of its special algorithm for security and accuracy. By viewing your data on Daysy and the Daysyview app, you can respond quickly to many of the aforementioned issues and get the support you need by sharing your data with your health team, and even joining a community group of other Daysy users! Sign. Us. Up.
Written by: Lizzy Steiner
Medically reviewed by: Heather Bartos, MD
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.
- “Pregnancy Tests.” Office on Women’s Health. U.S. Department of Health and Human Services, January 31, 2019. https://www.womenshealth.gov/a-z-topics/pregnancy-tests.
2 Fraser, Ian, Hilary Critchley, Michael Broder, and Malcolm Munro. “The FIGO Recommendations on Terminologies and Definitions for Normal and Abnormal Uterine Bleeding.” Seminars in Reproductive Medicine 29, no. 05 (2011): 383–90. http://www.pharllc.com/wp-content/uploads/2014/03/Fraser-Semin-Reprod-Med-2011.pdf.
3 “Menorrhagia (Heavy Menstrual Bleeding).” Mayo Clinic. Mayo Foundation for Medical Education and Research, July 15, 2017. https://www.mayoclinic.org/diseases-conditions/menorrhagia/symptoms-causes/syc-20352829.
4 “Anemia.” Mayo Clinic. Mayo Foundation for Medical Education and Research, August 16, 2019. https://www.mayoclinic.org/diseases-conditions/anemia/symptoms-causes/syc-20351360.
- Bull, Jonathan R., Simon P. Rowland, Elina Berglund Scherwitzl, Raoul Scherwitzl, Kristina Gemzell Danielsson, and Joyce Harper. “Real-World Menstrual Cycle Characteristics of More than 600,000 Menstrual Cycles.” Npj Digital Medicine 2, no. 1 (2019). https://doi.org/10.1038/s41746-019-0152-7.
- Pickett, Mary. “Polycystic Ovary Syndrome.” In Harvard Medical School Health Topics A-Z, edited by Harvard Medical School. Harvard Health Publications, 2017. http://i.ezproxy.nypl.org/login?url=https://search.credoreference.com/content/entry/hhphealth/polycystic_ovary_syndrome/0?institutionId=1961
- Davis, Susan R, and Sarah Wahlin-Jacobsen. “Testosterone in Women—the Clinical Significance.” The Lancet Diabetes & Endocrinology 3, no. 12 (2015): 980–92. https://doi.org/10.1016/s2213-8587(15)00284-3.
- “CYP19A1 Gene – Genetics Home Reference – NIH.” U.S. National Library of Medicine. National Institutes of Health. Accessed January 22, 2020. https://ghr.nlm.nih.gov/gene/CYP19A1.
- “Polycystic Ovary Syndrome – Genetics Home Reference – NIH.” U.S. National Library of Medicine. National Institutes of Health. Accessed January 22, 2020. https://ghr.nlm.nih.gov/condition/polycystic-ovary-syndrome.
10 “PCOS (Polycystic Ovary Syndrome) and Diabetes.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, August 12, 2019. https://www.cdc.gov/diabetes/basics/pcos.html.
11 Nandi, Anindita, Zijian Chen, Ronak Patel, and Leonid Poretsky. “Polycystic Ovary Syndrome.” Endocrinology and Metabolism Clinics of North America 43, no. 1 (2014): 123–47. https://doi.org/10.1016/j.ecl.2013.10.003.
12 “Polycystic Ovary Syndrome (PCOS).” Mayo Clinic. Mayo Foundation for Medical Education and Research, August 29, 2017. https://www.mayoclinic.org/diseases-conditions/pcos/diagnosis-treatment/drc-20353443.
13 Andres, Lisa Maria, and William A. Atkins. “Thyroid Gland.” In Gale Encyclopedia of Nursing and Allied Health, edited by Gale. 3rd ed. Gale, 2013. http://i.ezproxy.nypl.org/login?url=https://search.credoreference.com/content/entry/galegnaah/thyroid_gland/0?institutionId=1961
14 “Hyperthyroidism (Overactive Thyroid).” Mayo Clinic. Mayo Foundation for Medical Education and Research, January 7, 2020. https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/symptoms-causes/syc-20373659.
15 “Fibroids.” In Harvard Medical School Health Topics A-Z, edited by Harvard Medical School. Harvard Health Publications, 2017. http://i.ezproxy.nypl.org/login?url=https://search.credoreference.com/content/entry/hhphealth/fibroids/0?institutionId=1961
16 Marsh, Erica E., Ayman Al-Hendy, Dale Kappus, Alex Galitsky, Elizabeth A. Stewart, and Majid Kerolous. “Burden, Prevalence, and Treatment of Uterine Fibroids: A Survey of U.S. Women.” Journal of Women’s Health 27, no. 11 (2018): 1359–67. https://doi.org/10.1089/jwh.2018.7076.
17 Murji, Ally, Mohamed Bedaiwy, Sukhbir Sony Singh, and Olga Bougie. “Influence of Ethnicity on Clinical Presentation and Quality of Life in Women With Uterine Fibroids: Results From a Prospective Observational Registry.” Journal of Obstetrics and Gynaecology Canada, 2019. https://doi.org/10.1016/j.jogc.2019.10.031.
18 “Hyperprolactinemia.” In New Harvard Guide to Women’s Health, The, by Karen J. Carlson, Stephanie A. Eisenstat, and Terra Diane Ziporyn. Harvard University Press, 2004. http://i.ezproxy.nypl.org/login?url=https://search.credoreference.com/content/entry/hupwh/hyperprolactinemia/0?institutionId=1961
19 “pituitary gland.” In The Columbia Encyclopedia, by Paul Lagasse, and Columbia University. 8th ed. Columbia University Press, 2018. http://i.ezproxy.nypl.org/login?url=https://search.credoreference.com/content/entry/columency/pituitary_gland/0?institutionId=1961
20 “Primary Ovarian Insufficiency.” Mayo Clinic. Mayo Foundation for Medical Education and Research, October 22, 2019. https://www.mayoclinic.org/diseases-conditions/premature-ovarian-failure/symptoms-causes/syc-20354683.
21 Perimenopause.” In New Harvard Guide to Women’s Health, The, by Karen J. Carlson, Stephanie A. Eisenstat, and Terra Diane Ziporyn. Harvard University Press, 2004. http://i.ezproxy.nypl.org/login?url=https://search.credoreference.com/content/entry/hupwh/perimenopause/0?institutionId=1961
22 Aja, Susan. “Hypothalamus.” In Encyclopedia of Obesity, by Kathleen Keller. Sage Publications, 2008. http://i.ezproxy.nypl.org/login?url=https://search.credoreference.com/content/entry/sageobesity/hypothalamus/0?institutionId=1961
23 “Amenorrhea.” Mayo Clinic. Mayo Foundation for Medical Education and Research, July 25, 2019. https://www.mayoclinic.org/diseases-conditions/amenorrhea/symptoms-causes/syc-20369299.
24 Janssen, Math, Yvonne Heerkens, Wietske Kuijer, Beatrice Van Der Heijden, and Josephine Engels. “Effects of Mindfulness-Based Stress Reduction on Employees’ Mental Health: A Systematic Review.” PLoS One 13, no. 1 (January 24, 2018). https://doi.org/10.1371/journal.pone.0191332.
25 Gujral, Swathi, Howard Aizenstein, Charles F. Reynolds, Meryl A. Butters, and Kirk I. Erickson. “Exercise Effects on Depression: Possible Neural Mechanisms.” General Hospital Psychiatry 49 (2017): 2–10. https://doi.org/10.1016/j.genhosppsych.2017.04.012.
26 Komisaruk, Barry R., Carlos Beyer, and Beverly Whipple. The Science of Orgasm. Baltimore: Johns Hopkins University Press, 2006.
27 Baker, Fiona C., and Helen S. Driver. “Circadian Rhythms, Sleep, and the Menstrual Cycle.” Sleep Medicine 8, no. 6 (2007): 613–22. https://doi.org/10.1016/j.sleep.2006.09.011.
28 Pinheiro, Andréa Poyastro, Laura M. Thornton, Katherine H. Plotonicov, Federica Tozzi, Kelly L. Klump, Wade H. Berrettini, Harry Brandt, et al. “Patterns of Menstrual Disturbance in Eating Disorders.” International Journal of Eating Disorders 40, no. 5 (2007): 424–34. https://doi.org/10.1002/eat.20388.
29 Ålgars, Monica, Lu Huang, Ann F. Von Holle, Christine M. Peat, Laura M. Thornton, Paul Lichtenstein, and Cynthia M. Bulik. “Binge Eating and Menstrual Dysfunction.” Journal of Psychosomatic Research 76, no. 1 (2014): 19–22. https://doi.org/10.1016/j.jpsychores.2013.11.011.
30 “ACOG Committee Opinion: Obesity in Adolescents.” ACOG. The American College of Obstetricians and Gynecologists, September 2017. https://www.acog.org/Clinical-Guidance-and-Publications/Committee-Opinions/Committee-on-Adolescent-Health-Care/Obesity-in-Adolescents?IsMobileSet=false.
31 Schorr, Melanie, and Karen K. Miller. “The Endocrine Manifestations of Anorexia Nervosa: Mechanisms and Management.” Nature Reviews Endocrinology 13, no. 3 (April 2016): 174–86. https://doi.org/10.1038/nrendo.2016.175.
32 Patterson, Amanda J, Wendy J Brown, David Ck Roberts, and Michael R Seldon. “Dietary Treatment of Iron Deficiency in Women of Childbearing Age.” The American Journal of Clinical Nutrition 74, no. 5 (January 2001): 650–56. https://doi.org/10.1093/ajcn/74.5.650.
33 “Medicines That Can Cause Changes in Menstrual Bleeding.” Michigan Medicine. University of Michigan. Accessed January 22, 2020. https://www.uofmhealth.org/health-library/tv7209.