Vaginal odor can change from day to day during the menstrual cycle. An odor might be especially noticeable right after having sex. Sweating also can cause a vaginal odor.

Bacterial vaginosis is an overgrowth of bacteria typically present in the vagina. It's a common vaginal condition that can cause vaginal odor. Trichomoniasis, a sexually transmitted infection, also can lead to vaginal odor. A yeast infection usually doesn't cause vaginal odor.

Possible causes of unusual vaginal odor include:

1. Bacterial vaginosis (irritation of the vagina)
2. Poor hygiene
3. A forgotten tampon
4. Trichomoniasis

Less commonly, unusual vaginal odor may result from:

1. Cervical cancer
2. Rectovaginal fistula (an opening between the rectum and vagina that allows gas or stool to leak into the vagina)
3. Vaginal cancer