This piece was written by one of our contributors; medical student – Leah Crabtree.
Why have my periods stopped?
As something that women experience every single month, periods are extremely important to talk about and are certainly not talked about enough. They are tightly regulated, and influenced by many factors, so a good understanding of them is paramount in optimising women’s health.
What is Amenorrhoea?
Amenorrhoea is the medical term for ‘no periods’. It is expected that most girls would have started their period by the age of 15 but, as with everything body-related, people’s ‘normals’ are completely different (3). For some, their periods may start much earlier than 15, and for others, they may start later.
If someone we would expect to have periods, however, has never had a period, this is known as ‘primary amenorrhoea’ (2). In simpler terms, it is when a person never starts their periods.
If someone has had regular periods, but then their periods stop completely for more than 3 months, we call it ‘secondary amenorrhoea’ (2, 4). Secondary amenorrhea can also be diagnosed when someone has had irregular periods for a while and then has no periods at all for 6 months. Definitions do vary.
Sometimes periods can be missed for a couple of months due to stress, lifestyle changes, or just because our bodies aren’t playing ball that month (often for no clear reason). That’s okay, very common and usually nothing to worry about. Only when the missed periods continue for a few months does it become amenorrhoea.
Amenorrhoea is different from oligomenorrhoea, which is the medical term for ‘irregular periods’, but they often have the same causes. Oligomenorrhoea occurs when the gaps between your periods keep changing. You still have periods, unlike amenorrhoea, but the time between the periods changes unpredictably (5).
Back to basics
While a period (menstruation) can be a pain, literally and metaphorically, it does have a useful physiological origin (6).
Each month women’s bodies prepare for them to become pregnant. A host of hormones thicken the endometrium (lining) of the uterus (womb). During the month this lining becomes thicker and spongier, perfect for an egg to implant into (6-8). If we don’t become pregnant and the egg isn’t fertilised, this layer sheds, and we get the bleeding we know as a period. The cycle then begins again and the process repeats itself, month in and month out. The average cycle length of a period is 28 days with 5 days of bleeding, but some women may have longer or shorter cycles and periods (3). Understanding your ‘normal’ is really important, as you might be quicker to recognise if anything changes.
The hormones that regulate our periods are released from the brain. They travel through the body through a pathway known as the ‘hypothalamic-pituitary-ovarian’ axis, or the HPO axis. The hypothalamus (deep in the centre of our brains) releases a hormone called gonadotrophin-releasing-hormone, or GnRH. GnRH, just as its name suggests, signals to the pituitary gland (also found deep in our brains) to release hormones known as gonadotrophins(4, 8, 9).
The gonadotrophins crucial in menstruation are follicle stimulating hormone (FSH) and luteinising hormone (LH). They help with the release of an egg ready for potential fertilisation, and the stimulation of oestrogen and progesterone (more hormones). Oestrogen is involved in the development of the endometrium, while progesterone is crucial in maintaining it (8).
This complex pattern of hormones is finely regulated and inter-connected. It therefore follows that if the pattern of hormone release from the hypothalamus or pituitary changes, our periods may change, too.
Primary amenorrhoea causes
Doctors may want to investigate the possibility of primary amenorrhoea in two groups of patients. Firstly, if a girl hasn’t had a period by the age of 15, but has other signs of puberty such as breasts or pubic hair, primary amenorrhoea may be suspected. Additionally, doctors may want to investigate if a 13 year old girl hasn’t started her periods and has none of the expected hallmarks of puberty.
There are a number of causes of primary amenorrhoea, but they can usually be classified as either genetic or anatomic. Anatomical causes might be because someone is born without a uterus or vagina, or they may have defects in either that impair menstruation.
Genetic causes for primary amenorrhoea are also a possibility, and so doctors investigating primary amenorrhoea may order some genetic tests. Rare but possible causes of primary amenorrhoea may include problems with the hypothalamus (that releases GnRH), Turner syndrome (a rare chromosomal disorder), or androgen-insensitivity syndrome (another rare chromosomal disorder). It’s likely that these would be picked up early in life, even before the expected onset of periods.
If primary amenorrhoea is proven, treatments depend on the cause of the amenorrhoea. Surgery may be required for some women, while other women may have medication prescribed.
Secondary amenorrhoea causes
Causes of secondary amenorrhoea may be physiological, pathological and iatrogenic (due to medicine, surgery or a healthcare professional).
Physiological causes include:
NB: The most common cause of amenorrhoea in women is pregnancy, so a pregnancy test should be the first port of call for anyone who has experienced a new onset of period cessation. It might sound obvious, but it is a really important possibility to rule out. Additionally, women over the age of 40 should be considered to be at risk of early menopause, and so should be investigated for that (1, 2, 8).
Pathological causes include:
- Premature ovarian failure (due to chemotherapy, radiotherapy or an autoimmune condition)
- Thyroid disease (hypothyroidism or hyperthyroidism)
- Asherman’s syndrome
- Pituitary gland dysfunction (including hypopituitarism, head injury or prolactinoma)
- Hypothalamic dysfunction (stress, excessive exercise, weight loss or an abnormal BMI can lead to ‘functional hypothalamic amenorrhea’ whereby the hypothalamus, and so the HPO axis mentioned earlier, is affected, leading to amenorrhoea.) (4, 13)
* PCOS typically causes oligomenorrhoea, but can also lead to amenorrhoea (Saskia Craine and Maeve Hanan both wrote pieces on this). It’s important to remember that PCOS is not diagnosed just because of missed periods- you would need to have cysts in your ovaries or evidence of higher levels of male hormones for a diagnosis of PCOS to be confirmed. It is not an uncommon disease but there are lots of other causes of amenorrhoea besides PCOS, despite what it may sometimes sound like!
- Surgery (hysterectomy, endometrial ablation, ovarian surgery)
- Medication (including steroids, opiates, cocaine or antipsychotic medication)
- Contraception including the oral contraceptive pill, mini pill, depot injection or Mirena coil
NB: It’s not unusual to miss the odd period if you’re on the combined oral contraceptive pill, and some types of contraception (such as the mini pill, depot injection or Mirena coil) can stop your periods altogether (1). This is a normal and expected side effect of these contraceptive measures, but if you’re worried, your GP will be able to discuss these worries with you. Additionally, some women may experience ‘post-pill amenorrhoea’ which is a cessation of their periods after they stop taking the oral contraceptive pill. For some women, stopping the pill means that their periods take longer to come back than expected, or might be a bit irregular. This is usually temporary and just takes a couple of months to right itself. In some cases, however, the regular 28-day ‘pseudo’-cycles seen with the pill may have been masking an underlying abnormality such as functional hypothalamic amenorrhoea (mentioned above) or PCOS. These may have been present before the pill was started, or have developed during the time that the pill was being taken. If your periods haven’t returned after 3 months of stopping the pill, it’s worth seeing your GP (14).
What to do if you think you have amenorrhoea
First and foremost, a visit to your GP should be the first port of call if you’re worried about your periods and have missed more than 3 in a row. They will be able to work through taking a history, doing an exam, and may send off for some tests if they think it’s suitable. Lots of issues with periods work themselves out without any need for medical intervention, and a cause is never really known. This might be frustrating.
The cause of the amenorrhea will always be at the heart of any treatment.
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(2) NICE. Amenorrhoea. 2019. Available from: https://cks.nice.org.uk/amenorrhoea. [Accessed: 01/12/2019]
(3) Lacroix AE, Langaker MD. Physiology, Menarche. StatPearls. Treasure Island (FL): StatPearls Publishing LLC.; 2019.
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(5) NHS. Irregular Periods. 2018. Available from: https://www.nhs.uk/conditions/irregular-periods/. [Accessed: 01/12/2019]
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(10) BMJ. Assessment of secondary amenorrhoea. 2018. Available from: https://bestpractice.bmj.com/topics/en-gb/1102#referencePop1 [Accessed 07/01/2020]
(11) Meczekalski B, Katulski K, Czyzyk A, Podfigurna-Stopa A, Maciejewska-Jeske M. Functional hypothalamic amenorrhea and its influence on women’s health. Journal of endocrinological investigation. 2014;37(11):1049-56.
(12) Mitra A. The Gynae Geek. Harper Collins. 2019. P.39-53
(13) Kim JH. Body Weight Changes in Obese Women and Menstruation. Endocrinology and metabolism (Seoul, Korea). 2017;32(2):219-20.
(14) NHS. When will my periods come back after I stop taking the pill? 2018. https://www.nhs.uk/conditions/contraception/when-periods-after-stopping-pill/ [Accessed 07/01/2020]