Vaginal discharge is fluid that comes out of the vagina. It's mostly water, mucus, common (normal) bacteria, and cells from the vagina and cervix. Much like the mucus that benefits your nose, vaginal discharge benefits your vagina by cleaning and moistening it to prevent infections. If you still get your menstrual cycle, normal vaginal discharge is usually 1 to 4 milliliters of fluid per day, which is roughly 1/2 to 1 teaspoon. This fluid may be white or clear, thick or thin, and it is mostly odorless.

People with regular periods may notice thicker vaginal discharge around the middle of their cycle when they are ovulating or releasing eggs from their ovaries. Some people on birth control pills notice a thicker discharge as well. Your vaginal discharge may also increase when you're pregnant. These changes are normal.

However, changes in vaginal discharge can also occur because of infection (such as yeast infection), inflammation or changes in the normal bacteria that live in the vagina, which is called vaginitis.  Occasionally, abnormal discharge is a sign of more serious conditions, such as sexually transmitted infections or pelvic infection.

Consult your physician if you experience:

• Itching of the vagina or vulva, the area around the vagina
• Redness, pain or swelling
• Discharge that is foamy, greenish-yellow or bloody
• Discharge with foul odor
• Pain when urinating
• Pain during sex
• Lower abdominal pain or pelvic pain
• Fever

Most of the time, these symptoms can be treated easily with over-the-counter medication.

Jessica W. Kiley, MD, Vice Chair of Clinical Operations and Medical Director of Women's Health, Northwestern Medical Group