Oligomenorrhoea (infrequent or light periods) – types, causes and treatment

Normally, a healthy menstrual cycle lasts between 21 and 35 days. But what happens when more than 35 days pass between two periods, the bleeding is unusually light, and you have fewer than nine periods in a whole year?

These can all be signs of oligomenorrhoea – a menstrual disorder that can take several forms and may affect your fertility. In this article, we explain exactly what it means, why it happens, which types of oligomenorrhoea exist and how it can be treated.

What is oligomenorrhoea (infrequent periods)? 

Oligomenorrhoea is a menstrual disorder characterised by light and infrequent bleeding. Periods occur rarely (hence the name), at irregular intervals of more than 35 days, and the flow is very light.

What is the difference between oligomenorrhoea and amenorrhoea?

Both oligomenorrhoea and amenorrhoea are disorders affecting the frequency of menstrual bleeding – yet there is one important difference between them.

Women with oligomenorrhoea have infrequent, irregular bleeding, usually fewer than nine periods a year – but menstruation does occur.

Amenorrhoea, on the other hand, is characterised by the complete absence of menstruation for six consecutive months or longer.

How common is oligomenorrhoea? 

Around 12 to 15.3% of menstruating women experience oligomenorrhoea at some point in their lives. Among women with fertility problems, the figure is roughly 20%.

Oligomenorrhoea also frequently occurs alongside polycystic ovary syndrome (PCOS). It is estimated that 75 to 85% of patients with PCOS also have infrequent bleeding.

Types of oligomenorrhoea 

Depending on the cause and characteristics – hormonal or otherwise – several forms of oligomenorrhoea can be distinguished. Below we explain what each form means.

Hypogonadotropic oligomenorrhoea 

Hypogonadotropic oligomenorrhoea refers to infrequent bleeding caused by a deficiency of luteinising hormone (LH) and follicle-stimulating hormone (FSH). Anti-Müllerian hormone (AMH) levels remain normal in this form.

In short: the brain fails to send the appropriate signals for the ovaries to trigger ovulation and menstruation. Hypogonadotropic oligomenorrhoea occurs in women with delayed puberty, anorexia, bulimia, chronic stress, intense physical exertion, as well as in women with the so-called female athlete triad or hyperprolactinaemia.

Hypergonadotropic oligomenorrhoea

Hypergonadotropic oligomenorrhoea describes infrequent bleeding associated with very high levels of luteinising hormone (LH) and follicle-stimulating hormone (FSH), while anti-Müllerian hormone (AMH) levels are low.

These levels indicate impaired ovarian function and are typically found in menopausal women, in patients with Turner syndrome, and in women following certain treatments (e.g. chemotherapy, pelvic radiotherapy, removal of the ovaries).

Dysgonadotropic oligomenorrhoea 

In dysgonadotropic oligomenorrhoea, levels of luteinising hormone and follicle-stimulating hormone are normal or only slightly altered, yet the ovaries respond abnormally. This form of the disorder is typical of patients with PCOS (polycystic ovary syndrome).

Iatrogenic oligomenorrhoea 

Iatrogenic oligomenorrhoea is triggered by complications following surgery or as a side effect of certain treatments. It is characterised by infrequent bleeding after removal of the ovaries or uterus, after radiotherapy or chemotherapy, or after other treatments that affect the hormonal axis.

Causes of oligomenorrhoea 

Conditions that cause hormonal disturbances are the most common (though not the only) cause of infrequent bleeding. When an imbalance arises in the hormones produced by the glands and reproductive organs, this affects the regularity of the menstrual cycle and can trigger oligomenorrhoea. The most common causes include:

• Puberty: In the first few years after the first period, when hormone levels still fluctuate considerably, it is normal for bleeding to be irregular. However, if oligomenorrhoea persists for 3–4 months or progresses to amenorrhoea (complete absence of menstruation for six months), this can – even during puberty – be an early sign of polycystic ovary syndrome, Turner syndrome or adrenal hyperplasia.
• Hormonal imbalances: When such an imbalance occurs, the hormones that regulate ovulation and the menstrual cycle no longer function properly – which affects the heaviness and frequency of bleeding.
• Stress: During stressful periods, the body produces more cortisol, which may also be accompanied by increased insulin resistance and can disrupt the rhythm of the menstrual cycle.
• Polycystic ovary syndrome: PCOS leads to excessive production of androgens (such as testosterone), which can prevent ovulation and result in irregular bleeding.
• Bulimia/anorexia: Hormonal balance can be thrown off by hormonal fluctuations, which may impair normal ovarian function and the build-up of the uterine lining.
• Adrenal hyperplasia: This is characterised by excessive production of adrenal hormones, which inhibit the production of luteinising hormone and follicle-stimulating hormone and affect the menstrual rhythm.
• Thyroid disorders: Oligomenorrhoea can be triggered by both an underactive and an overactive thyroid.
• Diabetes mellitus: Studies link oligomenorrhoea to type 1 diabetes, which often occurs in underweight individuals, as well as to type 2 diabetes, which mainly affects those who are overweight.
• Perimenopause: In the absence of other causes explaining the lack of bleeding, oligomenorrhoea may be an early sign of the menopause.

Symptoms associated with oligomenorrhoea 

Oligomenorrhoea is itself a symptom of one of the conditions described above. The most common and most obvious sign is a delayed or absent period for more than 35 days.

The disorder may, however, also be accompanied by further symptoms, including:

• Mild abdominal pain
• Acne
• Weight gain
• Hair loss or increased body hair
• In some cases, infertility
• Headaches
• Vaginal discharge
• Hot flushes
• Visual disturbances

Oligomenorrhoea – how is it diagnosed? 

A gynaecologist diagnoses oligomenorrhoea based on your medical history and additional investigations:

• Medical history: This involves talking to the patient and asking about the heaviness of bleeding, the regularity of the cycle and any other relevant symptoms. As part of taking a history, the doctor will also learn about the patient's lifestyle, whether she suffers from chronic stress, whether she is approaching the menopause, whether she is a competitive athlete, or whether she has undergone particular treatments or surgery.
• Physical examination: Together with the medical history, a physical examination (face, chest, body) makes it possible to identify accompanying symptoms such as acne, as well as weight loss or gain.
• Gynaecological examination: This allows the doctor to examine the vagina and cervix and determine whether there are signs of inflammation, infection, bleeding or scar tissue that could affect the menstrual cycle.
• Pelvic ultrasound: This can detect polycystic or atrophic ovaries, as well as other abnormalities of the uterus and uterine lining that might be linked to oligomenorrhoea.

• Hormone tests: Blood tests allow measurement of luteinising hormone, follicle-stimulating hormone, anti-Müllerian hormone, oestrogen, progesterone, testosterone, prolactin, thyroid hormones and any other relevant hormones that can affect the regularity of the cycle. The results also make it possible to determine the type of oligomenorrhoea.

  

Oligomenorrhoea – treatment options 

The first step in deciding on treatment is identifying the cause precisely and correctly. Treatment for oligomenorrhoea depends on the underlying problem and may involve hormone therapy, surgery, or simply lifestyle changes.

Hormone therapy 

If oligomenorrhoea is caused by a hormonal imbalance, the doctor may prescribe various hormone treatments. Depending on the cause, these may include contraceptives, treatment with oestrogen, progesterone, anti-androgens, dopamine agonists, specialised preparations or other forms of hormone therapy.

Lifestyle changes 

If oligomenorrhoea is the result of chronic stress, excessive physical exertion or conditions such as PCOS, the doctor may recommend certain lifestyle changes. These usually include giving up competitive sport, psychological counselling, plenty of rest and a nutrient-rich diet.

Surgery

Surgery is recommended where there is a tumour stimulating excessive androgen production. The aim of treatment is to remove the tumour in order to restore hormonal balance and thereby automatically regulate the menstrual cycle.

Frequently asked questions about oligomenorrhoea

It is important to understand that oligomenorrhoea – just like menstruation itself – can look different for every woman, and its impact on health and daily life depends on the causes and individual circumstances. Below we have answered the most common questions about this menstrual disorder – in the hope of helping you understand it better and recognise when to seek medical advice.

How dangerous is oligomenorrhoea? 

Oligomenorrhoea in itself is not dangerous, but it can indicate a hormonal imbalance or a condition requiring treatment – particularly if it persists. If your period is suddenly more than 35 days late and very light, or if you have fewer than nine periods a year, you should see your gynaecologist for further investigation.

Is oligomenorrhoea normal during puberty? 

Yes, irregular and infrequent bleeding is common and normal in the first few years after the first period, as hormone levels fluctuate considerably. However, if the cycle has still not settled after 3–4 years, a gynaecological examination is advisable.

Does oligomenorrhoea affect fertility? 

Yes, oligomenorrhoea can affect fertility. Irregular cycles may indicate a lack of ovulation, which is essential for conception. That's why it's important to monitor your cycle and discuss these points with your gynaecologist if you are having difficulty getting pregnant.

Can stress cause infrequent menstrual cycles? 

Yes, stress can raise cortisol levels in the body and also interact with the hormones that control ovulation – which can delay your period or stop it altogether.

Can oligomenorrhoea occur after pregnancy? 

Yes, the menstrual cycle can remain irregular in the period after giving birth, particularly while breastfeeding, as prolactin (the hormone that stimulates milk production) can temporarily suppress ovulation.

Normally, periods gradually return to normal a few months after giving birth or after stopping breastfeeding. However, if oligomenorrhoea persists for a longer period or progresses to amenorrhoea, a medical examination is advisable.

Can contraceptives cause oligomenorrhoea? 

Yes, contraceptive pills affect the menstrual cycle and can lead to unpredictable, infrequent or light bleeding when you stop taking them or switch to a different preparation. The body needs time to restore hormonal balance and regulate the cycle – which can result in temporary oligomenorrhoea. If oligomenorrhoea persists, whether you are using contraception or not, you should see a doctor.

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