Why is my period irregular?

Why is my period irregular?

Publié par Krista Lowe le


“Why is my period irregular?” You’re not alone. It can be stressful not knowing when you’re going to get your period! Up to 14%¹ of people experience an irregular period. Tuning into your body and noticing the signs and symptoms around your period can give you some vital information about your health.


A regular cycle ranges from 26 to 32 days and if you notice that your period cycle is changing every month then this might be a sign that there is something going on with your period health. Also having signs that your period is about to start (cramping, bloating and PMS) without it actually starting is another sign that your period is becoming irregular. Changes in your flow like being heavy one month and light the next or changes in your period blood color can tell you information about your sex hormones.


Why is my period irregular?


Here are 6 common reasons periods can be irregular.




Each person responds to stress differently. Some people may feel stress in their shoulders or digestion, while others may notice it affects their period. The stress hormone cortisol is interconnected to your sex hormones estrogen and progesterone, so it’s possible that high stress has the ability to throw your cycle off completely!


Lack of sleep


Irregular sleep² patterns have shown to affect your menstrual cycle causing an irregular period. This is because your circadian rhythm has an impact on the release of your hormones. Both the quantity and quality of your sleep is important in keeping your circadian rhythm in a regular rhythm and therefore your menstrual cycle in a regular rhythm. Shift work and travelling through different time zones are common examples of how changes in your sleep can affect your period.


Changes in nutrition and alcohol intake


Increased alcohol, sugar and processed food consumption can affect your period. Alcohol has estrogenic³ effects on the body as well, as alcohol will get processed and detoxed through the liver before estrogen. The fiber in your diet, which can be lacking in some processed foods, is important in helping your bowel movements excrete estrogen. Sugar can increase inflammation, which can lead to an increase in bloating, heavy and painful periods.


Stopping birth control pill


The hormonal birth control pill or IUD regulates your period by giving you a dose of sex hormones; therefore, it’s very common to have an irregular period for the first three to six months after stopping birth control.




Perimenopause is the period of time that leads up to menopause. Menopause is when a person’s cycle has stopped for 12 consecutive months. Irregular periods⁴ are one of the main symptoms of perimenopause⁴ because less viable follicles will be produced and, therefore, causes a change in estrogen levels. You may also have cycles where an egg isn’t released by the ovary thus causing a decrease in progesterone levels. The fluctuations in these hormones cause irregular periods, mood swings, changes in weight, and troubles sleeping.


Hormonal imbalances


A pre-existing hormonal condition like PCOS and both an underactive and overactive thyroid⁵ condition can lead to an irregular cycle. PCOS can cause an increase in androgen levels (testosterone) and this can inhibit ovulation from occurring. PCOS is estimated to affect 1 in 10 people⁶ and along with irregular periods it can cause other symptoms like: acne, increased body hair, acne and weight changes. It’s important to reach out to a health care practitioner and test your hormone levels if you think you may have a hormonal imbalance.


What should I do about my irregular period?


The first step is to notice whether or not your period is irregular and how it is irregular. I always recommend that you track your period with a period app! Once you’re familiar with your cycle length, what your period flow looks like and the symptoms around your period it’s always best to talk to your health care practitioner. This way you will be prepared to discuss the ins and outs of your period health and with your health care practitioner you’ll be able to further investigate the causes of your symptoms!


  1. Sweet & Madsen (2012) Evaluation and Management of Abnormal Uterine Bleeding in Premenopausal Women. Am Fam Physician 85(1): 35-43 https://www.aafp.org/afp/2012/0101/p35.html

  2. Baker & Lee (2018) Menstrual cycle effects on sleep. Sleep medicine clinics 13(3): 283-294 https://www.sleep.theclinics.com/article/S1556-407X(18)30032-8/pdf

  3. Gavaler (1998) Alcoholic Beverages as a Source of Estrogens. Alcohol Health & Research World. 22(3) https://pubs.niaaa.nih.gov/publications/arh22-3/220.pdf

  4. Mayo Clinic (2019) Perimenopause. Retrieved from: https://www.mayoclinic.org/diseases-conditions/perimenopause/symptoms-causes/syc-20354666

  5. John Hopkins Medical (2021) Amenorrhea. Retrieved from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/amenorrhea

  6. OASH (2019) Polycystic ovarian syndrome. Retrieved from: https://www.womenshealth.gov/a-z-topics/polycystic-ovary-syndrome