Vaginal odor: causes and what it may indicate

Vaginal odor is a topic that can easily make you start worrying before there is any real reason to. Let's take a calm look: how the microflora works, what a fishy odor of discharge indicates, and at what point talking to a doctor stops being a formality.

How the vaginal microflora is organized

The vagina is a self-sustaining environment. In healthy girls and women aged 16–40, lactobacilli make up more than 95% of the entire microflora, while the remaining 5% account for more than 300 species of microorganisms. Lactobacilli produce lactic acid, so vaginal contents have an acidic reaction — pH 3.8–4.5. This environment suppresses the growth of Gardnerella, streptococci, and obligate anaerobes.

Acidic environment and changes in odor

In bacterial vaginosis, itching and soreness are usually absent, and a fishy odor is characteristic. The biocenosis is influenced by the phase of the cycle, pregnancy, menopause, and the use of antibacterial drugs. Douching and perfumed products increase the likelihood of bacterial vaginosis. If you notice changes in discharge or odor, this is a reason to discuss the situation with a doctor.

Fishy odor and bacterial vaginosis

A strong fishy odor of discharge, especially after sexual intercourse, is the most recognizable symptom of bacterial vaginosis. It is often accompanied by a change in color and consistency: discharge becomes grayish-white, thin, and watery. The mechanism is as follows: anaerobes that have replaced lactobacilli produce volatile fatty acids and amino acids, which break down into volatile amines — these produce the odor. There is no inflammatory reaction: leukocytes do not increase, which is why this is vaginosis, not vaginitis. Half of women with bacterial vaginosis notice no symptoms at all. Bacterial vaginosis is not classified as a sexually transmitted infection, but sexual activity can trigger it and transmit it to a female partner. Recurrence occurs in 50% of women, and the condition itself reduces the acidity of the environment and increases the risk of other infections.

Unusual odor and other symptoms

The cause cannot be determined by odor alone — this is done by a doctor based on the combination of signs. For example, gray-green discharge, which may have an unpleasant odor, occurs with trichomoniasis; there, itching, burning, and pain in the vagina and vulva, burning during urination are also possible, and often there are no symptoms at all.

White and gray-green discharge with odor

Color and consistency help narrow down the causes. In bacterial vaginosis, discharge is white or gray, thin, watery, sometimes frothy on examination. In a yeast infection, it is thick, white, cottage-cheese-like, may be watery and often without odor, while itching and redness are more pronounced. Gray-green discharge, frothiness, itching, or pain are a reason to see a doctor, not to choose a remedy based on an internet description.

How the cause is determined and when to see a doctor

During an appointment, the doctor asks about the history, performs an examination, assesses the color, consistency, and odor of discharge, and examines a sample of vaginal fluid under a microscope; sometimes additional tests are needed. At the same time, sexually transmitted infections are ruled out. Amsel clinical criteria: homogeneous gray-white discharge, pH above 4.5, fishy odor of discharge or upon adding 10% KOH, "clue" cells on microscopy — the diagnosis is made when three of four are present. Gram-stain microscopy on the Nugent scale: 0–3 points — normal, 4–6 — intermediate state, more than 6 — bacterial vaginosis. Gardnerella is detected in 95–100% of patients with bacterial vaginosis.

You should see a gynecologist if:

• you suspect bacterial vaginosis;
• your discharge has changed color or consistency;
• you are pregnant and have noticed a change in discharge;
• episodes recur more than four times a year.

A change in odor alone is not a reason to call an ambulance. 103 or 112 — for a life-threatening condition, such as signs of stroke or heart attack, and not because of odor as such.

This is reference material: it helps you navigate symptoms, but does not replace a doctor's consultation, which begins with an examination and tests.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer