When periods stop: amenorrhoea

If your periods stop after you’ve been having them, the first thing to think about is pregnancy. Clinicians call this secondary amenorrhoea. They will also look at your health history, your medicines and other possible causes.

If pregnancy is possible

The NHS says most pregnancy tests can be used from the first day of a missed period. If you don’t know when your next period is due, test at least 21 days after you last had unprotected sex. Follow the instructions for your test.

Call 999 now (UK) or 911 (US), or your local emergency number, if you have sudden severe tummy pain with marked dizziness or fainting.

Contact an urgent GP service or NHS 111 now (UK), or your doctor or urgent care service (US or elsewhere), if you could be pregnant and you have pain low in your tummy on one side, vaginal bleeding or pain at the tip of your shoulder, even without a positive pregnancy test. If you have these symptoms, don’t wait to repeat a test.

If a test is negative but you still think you could be pregnant, wait a few days and test again. If the second test is negative and your period still hasn’t come, talk to your GP or doctor. The hormones in contraceptive pills don’t stop a pregnancy test working.

When to book an appointment

In the UK, the NHS advises seeing a GP if you’ve missed your period 3 times in a row. It also advises a check if a missed period comes with symptoms such as weight change, tiredness, facial hair growth or skin changes. The same applies if your periods have become irregular.

US specialist guidance from ASRM suggests tests after more than 3 months without periods if your cycles used to be regular, or 6 months if they were irregular. These are different ways of saying when to get checked. They don’t mean you should wait if you might be pregnant or have other symptoms.

What might be affecting your cycle

Breastfeeding and some hormonal contraception can stop bleeding. Stress, sudden weight loss, higher body weight and hard exercise can also be linked with missed periods. Your clinician will look at all of these together. A record of your periods can’t tell you which one applies.

Conditions they may consider include an underactive or overactive thyroid, raised prolactin, premature ovarian insufficiency and PCOS. On the NHS website, you may now see PCOS called polyendocrine metabolic ovarian syndrome (PMOS). These conditions need different checks and treatments, even though they can all affect bleeding.

Functional hypothalamic amenorrhoea is when the brain’s hormone signals slow down. This can happen when you’re not eating enough for your activity, or when you’re under stress. It’s only considered once other causes have been ruled out. Checks include your eating and exercise habits, weight changes, sleep, mood and any past fractures.

What happens during the assessment

Your clinician may ask when your periods first started, what they were like before they stopped, and whether you’ve had any recent treatment or surgery. Depending on your history and examination, blood tests may include a pregnancy test, thyroid tests, prolactin and FSH. An ultrasound scan may help too. Not everyone needs every test.

Bring the names of your prescribed medicines and contraception. Describe what has changed, even if you’re not sure why. If eating, training or stress is hard to talk about, say so at the start. You could ask, “What are we checking first, and what happens if those tests don’t explain it?”

Care after a cause is found

Treatment depends on why your periods have stopped. For functional hypothalamic amenorrhoea, care may involve eating better, exercising less and psychological support. Your bones may also need checking. The Endocrine Society advises against using the pill just to bring back periods or to improve bone density in this condition.

While you recover from functional hypothalamic amenorrhoea, bleeding may be irregular and you can still get pregnant. If you want to avoid pregnancy, talk about contraception with your clinician. If you’re hoping to get pregnant, ask how that changes the care plan while your eating, activity and hormones recover.

Book with a GP in the UK, or your doctor in the US or elsewhere, following the advice above. Ask when your results will be looked at and who to contact if your symptoms change.