Why is my menstrual cycle so short?

Just before we launch into the information today, if you have noticed that your periods or menstrual cycle have changed after having covid or after the vaccination. I have a masterclass replay for you ‘Periods not the same after covid’ discussing what changes research has found to periods and the menstrual cycle, why it is happening & what can be done to help support your periods, hormones & menstrual cycle. 

You can purchase the masterclass replay below:


Let’s discuss what a short menstrual cycle is & the reasons why your menstrual cycle could be too short.

What is a menstrual cycle?

The word menstrual comes from the latin word mensis, which means month. Menstrual cycle length is about the same as the length of a lunar month which is 29.5 days (the period of time it takes to go from new moon to the next new moon). The new moon is when the moon looks like a little skiny sliver and then it goes into a full moon and then back to the new moon.

A menstrual cycle is based on the time from the first day of your period to the day before your next period. It also includes your menstrual phase so the first day of your period to the last day, follicular phase which is from day 1 of your period until ovulation, ovulatory phase which is around the time of ovulation, and your luteal phase which starts the day after ovulation up until the day before your next period.


What is considered a normal menstrual cycle?

There does seem to be variations of this in the research and according to the opinions of several practitioners. So keep that in mind.

A normal healthy menstrual cycle length is considered to be

  • 26 days minimum up to 35 days maximum

  • With a period of 4-7 days in length

  • Blood loss of 30-40ml is considered normal, but an upper limit could be 60-80ml.

  • 80ml or more though is generally considered to be menorrhagia or heavy periods. If you need to change your pad or tampon every 2 hours or more, because it is fully soaked with blood that is considered to be heavy.


What is considered to be a short menstrual cycle?

  • A short menstrual cycle is generally if it is less than 25 days approximately. This is where there may have been a luteal phase defect whereby the post ovulation phase is short & progesterone is decreased. If you have a shorter menstrual cycle this means that you will be getting your period more often.

  • In a short menstrual cycle, ovulation may have not taken place or occurred a lot earlier than expected.

  • Research has shown that you have a menstrual cycle of less than 26 days this can reduce your fecundity (ability to conceive each month).

  • And if it is less than 21 days, that will generally be an anovulatory cycle. Remember the luteal phase needs to be over 10 days in length in order for the endometrium (lining of the uterus) to be prepared for a fertilised egg. If it is shorter than 10 days this indicates that there is not enough progesterone being produced and the lining is not adequate therefore it is considered to be an infertile cycle.

What can cause a short menstrual cycle?

  • Anovulation (lack of ovulation)

  • Hypothyroidism (underactive thyroid)

  • Hyperthyroidism (overactive thyroid)

  • Stress

  • Weight loss

  • Weight gain

  • Fibroids

  • Ovarian cysts

  • Over exercising

  • After covid or vaccination

  • Breast feeding

  • Perimenopause – this is the journey towards Menopause and it is due to reduction in oestrogen levels

 What is a big factor in your menstrual cycle length?

Ovulation plays a role in your menstrual cycle because if it doesn’t occur for instance your follicle isn’t released and then the little sac known as the corpus luteum isn’t present to produce progesterone in the luteal phase. As a result, your progesterone levels will decrease, and you will get your period sooner.

For those of you that don’t know me, my name is Michelle Cooke, Period & Hormone Naturopath. I am also a certified Natural Fertility Educator so can teach you to track your cycle and identify ovulation. If you are interested in working together please contact me.

have you been

 experiencing period or menstrual cycle changes after covid or after the vaccination?

I have a masterclass available for you:

‘Periods not the same after covid’

We  will discuss what these changes are to periods and the menstrual cycle, why it is happening (for both after covid & the vaccine according to the research) & what can be done to help support you periods, hormones & menstrual cycles. 

90 min Masterclass

for ONLY $29 (for a limited time) 

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