Amenorrhoea (Absent Periods)

Amenorrhoea means the absence of menstrual bleeding. It refers either to never having had a period (primary amenorrhoea) or to periods stopping in someone who previously had regular or irregular periods (secondary amenorrhoea). Pregnancy, breastfeeding and menopause are physiological causes. Outside these situations, hormonal, lifestyle-related or anatomical causes are investigated. The information below offers a general overview and does not replace an individual diagnosis or treatment advice.

How do primary and secondary amenorrhoea differ?

Primary amenorrhoea means periods have never started during adolescence. Secondary amenorrhoea means periods have stopped for longer than expected after previously occurring. Both require a pregnancy test and medical assessment.

Periods are regarded as an indicator of general health in girls and women, so their onset and pattern are discussed during health checks. Irregular or very heavy periods that still occur are a different symptom group, assessed separately.

When does amenorrhoea need assessment?

The age and duration criteria used for assessment vary between sources and countries, so consulting a doctor is recommended. In general, medical advice is recommended in the following situations:

• Periods not starting despite signs of puberty, such as breast development, or puberty signs not starting at all.
• Periods absent longer than expected after previously being regular.
• A very prolonged absence of periods in someone with irregular cycles.

If pregnancy is possible, a pregnancy test comes first; a negative result does not make further investigation unnecessary.

What are the physiological causes of amenorrhoea?

Pregnancy, breastfeeding and menopause are physiological causes of absent periods. Pregnancy is the first condition to rule out in every woman of reproductive age who is not having periods.

Can amenorrhoea have a hormonal or ovarian cause?

Yes. Polycystic ovary syndrome, thyroid hormone disorders, raised prolactin and early loss of ovarian function (premature ovarian insufficiency) are common causes. Each requires separate assessment and treatment.

Can excessive exercise or low weight stop periods?

Yes. Excessive exercise, low weight, eating disorders and severe stress can reduce reproductive hormone signals from the hypothalamus in your brain, stopping periods. This is called functional hypothalamic amenorrhoea. Missing periods in an athlete should not be regarded as normal; low energy intake and intense exercise may also affect bone health.

Can amenorrhoea result from uterine or genital tract structure?

Yes. Congenital differences in the uterus or vagina, or uterine adhesions, may prevent menstrual blood from flowing out or forming. Genetic causes may also fall within this group. Detailed assessment is needed. Such a diagnosis can be upsetting for young girls and families; gradual, calm discussion with the doctor and support can help.

How is amenorrhoea diagnosed?

Assessment starts with periods, weight changes, exercise, diet, medicines and accompanying symptoms such as milk discharge, excess hair growth or headache. Examination and a pregnancy test are performed. Thyroid-stimulating hormone, prolactin and FSH are generally measured; ultrasound or other imaging may be used if needed. Further hormonal or genetic tests are requested in some circumstances. Your doctor selects tests according to age, symptoms and findings; not everyone needs every test.

How is treatment for amenorrhoea decided?

There is no single treatment; the approach addresses the cause:

• Adjusting lifestyle, diet and exercise with medical advice.
• Medicines for thyroid or prolactin disorders.
• Hormone treatment when considered necessary.
• Surgery or a procedure for anatomical problems.

Using medicines or herbal teas on your own to bring on a period is not recommended. These may conceal the cause and lead to a pregnancy being missed.

Can amenorrhoea affect fertility and bone health?

Missing periods may understandably cause fertility concerns. Identifying the cause and an appropriate approach helps manage anxiety and plan suitable steps for a future pregnancy.

The effect on fertility depends on the cause. Targeted treatment and monitoring may make pregnancy possible in some circumstances, but results vary and cannot be promised. Prolonged low hormone levels may affect bone density, so prolonged absence of periods needs assessment without delay.

A delayed period after stopping the contraceptive pill is temporary in most cases. However, if periods remain absent, the cause should be investigated.

When should you avoid delaying an appointment for amenorrhoea?

Even if not an emergency, do not delay an appointment for:

• Puberty signs or periods not starting when expected in a young girl.
• Prolonged absence of periods.
• Previous fracture or stress fracture.
• Excess hair growth or a deepening voice.