why your period might be missing

Five Reasons Why Your Period Is Missing

Has your period gone missing? Amenorrhoea is the term given for absent menstruation.


Amenorrhoea can be classified into two categories: primary amenorrhoea and secondary amenorrhoea.


Primary amenorrhoea is the absence of a menstrual cycle at 16 years of age in the presence of normal growth and secondary sex characteristics (breast, pubic hair), or the absence of a menstrual cycle at age 14 with no presence of secondary sex characteristics. 


Secondary amenorrhoea is when consistent menstrual cycles have been established that have then stopped for three or more cycles.

Let’s explore some common causes for secondary amenorrhoea.



The HPO axis (hypothalamic-pituitary-ovarian) which governs the whole menstrual cycle is delicate, precise, and vulnerable to external influences. The hypothalamus is constantly scanning our environment and assessing for potential dangers or threats. If our hypothalamus perceives we are under stress, whether it is perceived stress, emotional,
physical, environmental etc, the hypothalamus can determine it is not an ideal time to be ovulating (and potentially fall pregnant) and stop communication with the ovaries. This can pause ovulation which then pauses our menstrual cycles.


Following on from above, undereating and/or having a low body weight is a stress on the body that can also stop menstruation. The process of ovulation is an energy expensive process. Many nutrients are required for maturing an egg to ovulation as well as maintaining progesterone levels after ovulation. If we don’t have the extra resources to maintain both ovulation and progesterone production, ovulation may stop, resulting in absent periods. Low body weight/low body fat in itself can also stop ovulation/menstruation. Body fat is an active tissue in the body, almost similar to an organ. Body fat communicates to other organs and endocrine glands in the body. If there is low body fat, this commonly coincides with low oestrogen. A certain amount of oestrogen is required to maintain regular, ovulatory menstrual cycles.


Polycystic ovarian syndrome (PCOS) is a metabolic condition that can impact the regularity of ovulatory menstrual cycles. Some common signs and symptoms associated with PCOS can include metabolic dysfunction, acne, weight gain, hair thinning/hair loss, hirsutism, polycystic appearing ovaries on an ultrasound, irregular or absent menstrual cycles. Not all of these signs/symptoms need to be present to have PCOS. The diagnosis of PCOS should be determined via a combination of assessing symptom picture, blood tests, and ultrasound.



Have you stopped the oral contraceptive pill and then wondered where your period has gone? This is a very common scenario for a lot of women! It is important to remember that your menstrual cycle didn’t stop after you stopped the pill, it stopped when you started the pill, as the pill stops the HPO axis/ovulation/menstrual cycle. If you have been off the pill for longer than 3 months and there is no sign of ovulation or your period returning, it’s time to do some investigating!


The thyroid influences the functioning of every cell in the body, including the ovaries! Having a low functioning thyroid can impact how well a follicle grows and how well an egg can mature to ovulation. If the thyroid is very compromised and not able to function optimally, this can stop ovulation altogether resulting in absent periods. It’s important to remember that many different factors influence thyroid function and it’s vital to discover what your root cause is to help regain your menstrual cycle.


Last but not least, we can’t forget pregnancy! If you have not had your period for a while, it is of course always important to rule out pregnancy when investigating why.


It is also crucial to remember it is possible to fall pregnant before your period returns, as ovulation and fertility will precede the return of your period. So whilst your period is seemingly absent, if you are trying to avoid pregnancy you should still be thinking about implementing your chosen method of contraception. Did you know tracking your BBT even when your periods are absent can help you to know when that first period will return? Very handy information in our opinion! Here at Femtek we love supporting women through all stages of life!

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