Can letrozole stop your period?

Letrozole is an aromatase inhibitor. It reduces the amount of oestrogen made by the body, which is part of how it treats some hormone-sensitive breast cancers. Lower oestrogen can make periods less regular, lighter, or absent. It can also bring symptoms such as hot flushes, night sweats, vaginal dryness, or changes in sleep and mood.

A period stopping does not by itself show whether treatment is working. If you were still having periods before treatment, your clinician may need to check whether your ovaries are still active and whether another treatment is needed alongside letrozole. Pregnancy can be possible for some people, so ask what contraception is suitable; do not assume that absent bleeding rules pregnancy out.

Keep taking letrozole exactly as prescribed unless your oncology team tells you to stop. Record the date of your last period, any spotting, and symptoms such as pelvic pain or hot flushes. Tell the team about a new or persistent change, especially if your periods had already stopped and bleeding starts again.

Do not restart or change hormone medicines, supplements, or contraception without checking first, because some products may not fit your cancer treatment. Your clinician can decide whether you need a pregnancy test, blood tests, a review of ovarian function, or advice for side effects. Vaginal moisturisers and other symptom treatments may be options, depending on your cancer history.

Contact your oncology team promptly about unexpected vaginal bleeding, repeated spotting, significant pelvic pain, or a possible pregnancy. Seek urgent medical help for heavy bleeding with dizziness or fainting, sudden chest pain, severe breathlessness, new weakness on one side, or swelling and pain in one leg. These symptoms need assessment rather than being attributed automatically to letrozole.

Ask: Is my stopped period an expected effect in my situation? Do I need a pregnancy test or tests of ovarian function? Should I use contraception, and which options are appropriate with my cancer treatment? What should I do if bleeding returns? Which treatments can help hot flushes, vaginal symptoms, or bone health without interfering with letrozole?