Fishy smell after your period: what to know

Menstrual blood can temporarily alter vaginal acidity and make an existing odour more noticeable. A strong fishy smell with thin grey or white discharge commonly fits bacterial vaginosis, a change in the normal balance of vaginal bacteria. Trichomoniasis and other infections can also cause odour, irritation, burning, or discomfort during sex. Smell alone cannot identify the cause, and it is not a sign that you are unclean.

Notice whether the odour persists after the period, whether discharge has changed, and whether there is itching, burning, pelvic pain, fever, or pain when passing urine. A clinician may examine you and test a sample before recommending treatment.

Wash the vulva gently with water or a mild unscented cleanser, then dry carefully. Avoid douching, scented wipes, deodorants, and perfumed products because they can disturb the vaginal environment. Do not use leftover antibiotics or self-treat based only on smell. Arrange an appointment if the odour lasts, returns after each period, or comes with unusual discharge or irritation.

Get prompt medical help for fever, worsening lower abdominal or pelvic pain, vomiting, feeling very unwell, or bleeding outside your expected period. Seek advice sooner if you are pregnant, have a new sexual partner, or may have been exposed to a sexually transmitted infection.

Could this be bacterial vaginosis or another infection? Do I need a swab or sexually transmitted infection test? Which treatment is suitable, and what should I do if the smell returns after treatment?