Is Vaginal Odor Normal?
The Vagina in a Nutshell
Vaginal odor is determined by its microbial environment, and multiple factors have the ability to disrupt the microbiome. Similar to other areas in the body, there are healthy and pathogenic bacteria in the vaginal region; it is this balance that determines vaginal odor. ‘Healthy’ bacteria, namely lactobacillus, inhibit the growth of pathogenic bacteria. Lactobacilli maintains vaginal health by keeping a low pH level, a condition inhibiting pathogenic bacterial growth. A decrease in number of lactobacilli and a subsequent increase in pH disrupts the vaginal microbiome and can result in development of a fishy odor.
So, Is Vaginal Odor Normal? Yes.
Is there a specific scent a vagina must have? No. A vagina will never be odor-free, and each person usually has a different odor. There are normal conditions under which vaginal odors may increase. However, a malodorous vagina may be a sign of an infection or abnormal condition that requires medical intervention.
Blood has a distinct smell. During menstruation, the body sheds roughly 20 mL to 60 mL or 4 to 12 teaspoons of blood. In addition to blood, menstrual fluid contains tissue, mucous, and bacteria. This is why the vaginal odor during a woman’s period has a distinct smell, unlike blood from other areas of the body. Pleasantness and intensity of the vaginal odor can also depend on the ovulatory phase of a woman.2
Bacterial vaginosis (BV) is an infection in which there is an overgrowth in a variety of pathogenic vaginal bacteria. When the number of lactobacilli decreases, other bacteria can over-grow. In the case of BV, gardnerella vaginalis is the most common bacteria that overgrows. Symptoms may include gray or white discharge with a fish-like odor. It is the most common vaginal infection to produce an altered vaginal odor and occurs more commonly after intercourse and menstruation due to the presence of semen and blood.1
Yeast infections occur when there is an overgrowth in yeast, namely candida albicans. This occurs when the normal acidity of the vagina is disrupted, or when there is a hormonal imbalance. Yeast infections result in a cottage cheese-like discharge (thick and white); however, there is no unusual odor of the vagina.
Trimethylaminuria, known generally as fish odor syndrome, is caused by the impaired oxidation of trimethylamine. Normally, the liver oxidizes the choline to a non-odorous compound. Excess intake of trimethylamine-rich foods can exceed the liver’s capacity to perform this function, leading to the individual emitting a fishy odor through body fluids, including the vagina.3 This can be worsened by eating foods rich in choline and carnitine, which are found in egg-yolk, liver, kidney, soybeans, peas, and salt-water fish.4
While vaginal odor can be indicative of increased bacteria growth, one does not always need to be alarmed. It is normal for healthy vaginas to emit odor as a result of physiologic functions. From menstrual cycles to diet, vaginal odors can occur. However, if there is any concern for infection including abnormal discharge, pain, or inflammation, one should consult a healthcare provider.
- Livengood CH, Thomason JL, Hill GB. Bacterial vaginosis: diagnostic and pathogenetic findings during topical clindamycin therapy. Am J Obstet Gynecol. 1990;163(2):515-520.
- Doty RL, Ford M, Preti G, Huggins GR. Changes in the intensity and pleasantness of human vaginal odors during the menstrual cycle. Science. 1975;190(4221):1316-1318.
- Rehman HU. Fish odor syndrome. Postgrad Med J. 1999;75(886):451-452.
- de la HUERGA J, POPPER H. Urinary excretion of choline metabolites following choline administration in normals and patients with hepatobiliary diseases. J Clin Invest. 1951;30(5):463-470.