Irregular Periods: The Why (and if) Behind Your Period Being Late
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Irregular Periods: The Why (and if) Behind Your Period Being Late

by Aisle Team
Irregular Periods: The Why (and if) Behind Your Period Being Late

The ritualistic aspect of having a regular period has provided a lot of information and guidance to me over the years. Knowing that my period is going to come around a certain time allows me to plan, both emotionally, logistically and physically. Its imminent arrival reminds me and allows me to rest, and nourish myself with certain foods and specific movements. But that deep awareness can be hard to tap into when the menstrual clock doesn’t seem to be wound right each month. 

When a period is late or irregular, it can be an indicator of many things. However, before we get into the grit of it, let’s define what being late actually is. 

What counts as a regular period? 

Anywhere between 21-35 days for adults and 21-45 days for teens is considered a regular menstrual cycle. According to this 2020 study, only 16 percent of people with periods have a 28-day cycle. 

How many days late is an irregular period? 

7 days past the expected start of your period, is considered late. If your period is 7 days late and you are wondering about the possibility of pregnancy, this would be a good indicator to get a test. 

However, what determines an irregular period that may be caused by an underlying issue, will depend on a few things: how regularly your period is late, how drastically different your periods are in length and how infrequent they are. 

This is best measured over the course of the year. Fewer than 6-8 periods a year, is considered oligomenorrhea, a medical term for infrequent menstrual periods. 

Amenorrhea refers to the absence of menstrual periods. It is classified as primary (when menstruation has not started by 15 years of age) or secondary (when menstrual periods are absent for more than three to six months in an individual who previously had a period). 

What are some reasons that my period is irregular? 

The menstrual cycle, being an integral intersection of many systems and parts of the body, is a strong indicator of one's health status. Therefore, there is an exhaustive list of reasons why your period may be irregular or infrequent. Here are some of the most common reasons for irregular or infrequent periods. 

  • Polycystic Ovarian Syndrome and Endometriosis 

    • Menstrual cycle disorders such as PCOS and Endo affect the hypothalamus, pituitary gland, ovaries, uterus, cervix or vagina all key players in menstruation and can impact the regularity and occurrence of a period. 
  • Disordered Eating 

    • Energy deficiency caused by many eating disorders triggers a fall in the follicle-stimulating hormone (FSH) and the luteinizing hormone (LH) which are integral to a healthy cycle. 
  • Depression

    • High levels of corticotropin-releasing hormone and cortisol are present in those with depression, which inhibits the release of LH, therefore impacting menstruation
  • Stress 

    • Studies have shown that constant stress on the body, emotional and/or physical, can put the hypothalamic-pituitary-adrenal axis (your body’s center for responding to stress and releasing cortisol and adrenaline) out of whack. This causes a ripple effect, as the HPA axis is responsible for your LH, which will in turn impact your period. 
  • Hormonal Birth Control

    •  When coming off birth control, your cycle can take 3-6 months to start again. If your cycle does not return after those 6 months, that warrants a trip to the doctor. 
  • Perimenopause 

    • Individuals who are 35 and over may experience longer or shorter periods, which may mean you are entering perimenopause, the transition before menopause. 
  • Thyroid Problems 

    • Thyroid hormones have a direct impact on the release of reproductive hormones, so whether you have an overactive or underactive thyroid, this could lead to irregular periods. 
  • Puberty 

    • After menarche (the first time you get your period), it can take 3 years for cycle to regulate itself into a consistent rhythm. 
  • Breastfeeding 

    • Breast milk has a hormone called prolactin, which is known to impact ovulation. It is perfectly normal to not have a period in the early stages of breastfeeding. 

Why should I worry about a constantly irregular period? 

The frequency and quality of your period provides you with vital information about the health of your body and the stability of your hormonal architecture at that time. To ignore a regularly infrequent or absent period is ignoring what could be a warning or a sign of an underlying menstrual cycle disorder or even just a call to consider making some necessary lifestyle changes. 

How do you fix an irregular period? 

The first step is understanding why your period is irregular, which will most likely be the hardest. The process of diagnosing the root cause of your irregular period can be daunting, and not always made easy by certain medical systems, due to the lack of research and validation of menstrual health. So be prepared to be resiliently patient, lean on your community, and be your own advocate in situations of dismissal or disregard. 

Once you know the cause, it will hopefully provide some insight into next steps for you and certain supports that are available to you. 

Whilst self-diagnosis is not something to rely on for treatment, self-knowledge is hugely powerful in the process of healing. Keeping a journal/calendar to track the infrequencies of your period and how your body is feeling throughout your irregular cycles, can be a great way for you to gain insight into the messages your menstrual cycle is sending. 


Ella Adkins is a writer, teacher and occupier on the ancestral homelands of the Sḵwx̱wú7mesh, Stó:lō and Səl̓ílwətaʔ/Selilwitulh  and xʷməθkʷəy̓əm Nations. Her work has been featured in Femme Art Review, Peripheral Review, SAD Mag, ReIssue and Public Parking.


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