Secondary amenorrhoea (periods that have stopped): causes, tests and treatment in the UK

Amenorrhoea means the absence of periods. NICE Clinical Knowledge Summaries distinguish primary amenorrhoea, where periods have never started by the expected age, from secondary amenorrhoea, where periods that were established have stopped for 3 cycles or for 6 or more months. This page covers the second type.

The NHS notes that periods vary: for most women they come around every 28 days, but cycles of between 21 and 35 days are common, and periods last between 2 and 7 days. The NHS says that changes in your periods do not necessarily mean there is a problem, but they do need to be investigated. Stopping altogether for months is a clear reason to seek advice.

Some causes are normal and physiological, such as pregnancy, breastfeeding and the menopause. Others reflect a medical condition, a medicine or a life situation. NICE CKS says amenorrhoea may be physiological, pathological or iatrogenic, meaning caused by medical treatment.

NICE CKS says there are many possible causes of amenorrhoea, including physiological states, outflow tract obstruction, genetic and congenital conditions, and disorders of the ovaries, hypothalamus, pituitary gland and other endocrine glands. The more common causes of secondary amenorrhoea are summarised below.

The absence of periods is the main sign, but accompanying features help a GP to identify the cause. Mention any of the following when you attend.

• Possible pregnancy, or recent childbirth or breastfeeding.

• Weight loss or weight gain, intense exercise, or changes in eating.

• Acne, extra facial or body hair, or other signs of high androgen levels.

• Hot flushes, night sweats or vaginal dryness.

• Milky discharge from the breasts or headaches and vision change.

• Recent surgery on the womb or cervix, or a severe pelvic infection.

• Medicines you take, including contraception and antipsychotics.

NICE CKS says a thorough history and examination should be done to help identify the cause, and that a pregnancy test is a sensible first step. Preliminary investigations that may be considered in primary care include an ultrasound, serum prolactin, thyroid-stimulating hormone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), oestradiol and total testosterone if there are features of androgen excess.

The NHS adds that if you have taken a pregnancy test with a negative result and have missed 3 consecutive periods, your GP will investigate the cause and recommend any necessary treatment. Bleeding between periods, bleeding after sex or bleeding after the menopause should always be checked by a doctor.

NICE CKS advises referral to a gynaecologist for secondary amenorrhoea if FSH and LH are elevated in someone younger than 40, there has been recent uterine or cervical surgery or a severe pelvic infection, there is infertility, or the diagnosis of PCOS is unclear or has complications that cannot be managed in primary care.

Referral to an endocrinologist is advised for hyperprolactinaemia, low FSH and LH, a raised testosterone not explained by PCOS, or features of Cushing's syndrome or late-onset congenital adrenal hyperplasia. Amenorrhoea due to PCOS, hypothyroidism, menopause or pregnancy is managed in primary care where appropriate. If an eating disorder is suspected, NICE CKS advises a prompt referral to an age-appropriate community eating disorders service.

Treatment depends on the cause. Where it is due to weight loss, excessive exercise, stress or chronic illness, NICE CKS says it may be managed in primary care once an endocrinologist has assessed and excluded other hypothalamic or pituitary causes, such as a tumour. Hypothyroidism is treated with thyroid hormone, and PCOS through lifestyle changes and, where needed, hormonal or other treatment chosen by the GP or specialist.

Long-term absence of periods can matter for bone health and, for those who want a pregnancy, for fertility, so it is worth finding the cause even if the absence of periods does not itself feel like a problem. Your clinician can explain what applies in your case.

On the NHS the route is a GP appointment, a pregnancy test and blood tests and perhaps a pelvic ultrasound, with referral to gynaecology, endocrinology or an eating disorders service where needed.

Some people choose a private gynaecologist or endocrinologist for quicker scans and hormone tests. Share the results with your GP, because treatment such as contraception, thyroid medication or bone health monitoring is often managed in primary care.