Summary

The vagina is a thin muscular tube-like structure extending from the cervix (narrow passage forming the lower end of the uterus) to the vaginal opening between legs in women. It helps to pass blood out during periods, hold sperms for a while until they pass into the uterus and acts as a channel to facilitate normal delivery. To keep it clean and hygienic, vagina is constantly lubricated with a clear white fluid called the vaginal discharge.

In healthy conditions, the vagina is moist with no itching, foul odour, or abnormal discharge. In case of an infection, however, there is a change in the odour, colour, quantity, and consistency of the vaginal discharge. Bacteria, viruses, fungi, or parasites are the common causes of vaginal infections that result in a vaginal discharge with an unpleasant smell. Other conditions that result in foul vaginal odour include lack of hygiene, genetic disorder called fish odour syndrome (primary trimethylaminuria), menstrual bleeding, post-delivery phase, and more. Vaginal odour also undergoes changes during the monthly menstrual cycle with unpleasant odour present more towards the end than at the start of the cycle or mid-cycle.

Diagnosis of bad vaginal odour is primarily clinical and might be corroborated with further testing of the vaginal discharge for the confirmation of diagnosis. Appropriate treatment of the infection and adequate self-care to maintain vaginal hygiene helps to avoid foul vaginal odour. 

  1. What is Vaginal odor
  2. Types of Vaginal smell
  3. Vaginal odor symptoms
  4. Causes and risk factors of Vaginal odor
  5. Vaginal smell prevention
  6. Vaginal odor diagnosis
  7. Vaginal odor treatment
  8. Vaginal odor prognosis and complications

Vaginal odour commonly arises from the discharge secreted by different glands (Bartholin’s glands) present in the vaginal wall. In healthy conditions, the vaginal odour is not foul, but the smell changes in different phases of the monthly cycle. Vaginal discharge at the end of the menstrual cycle is more intense (no foul odour) than at the beginning and ovulation period of the menstrual cycle. Lactobacilli that are present inside the vagina also produce a chemical called hydrogen peroxide that kills infectious bacteria and the resultant odour-producing infections.

Imbalance in the growth of the normal vaginal organisms (commensals) or change in the vaginal pH due to perfumed sprays or soap or gel used for douching (cleaning vagina), perfumed wipes, and lack of hygiene are some of the common reasons for the growth of infectious organisms and bad vaginal odour.

Vaginal discharge with characteristic odour is usually associated with certain types of infections. Some of the commonly occurring types of vaginal odours  include:

  • Fish-like odour
  • Musty odour
  • Sweet odour
  • Metallic odour

Among the different organic compounds, lactic acid and acetic acid are the main chemical compounds present in vaginal discharge throughout the menstrual cycle. Changes in the concentration of these compounds are responsible for changes in the odour of vaginal discharge.

In healthy condition

  • Vaginal odour at the beginning of the menstrual cycle and during the ovulation phase is mild in intensity than at the end of the menstrual cycle when it has a metallic smell.
  • The odour of vaginal discharge after the delivery of a baby is stale and musty smelling or unpleasant. (Read more: Vaginal discharge during pregnancy)
  • Vaginal odour has a fish-like smell for some duration after sexual intercourse due to the collection of semen. Research studies have proven that vaginal odour is different before and after sexual intercourse.
  • A sweet vaginal odour may also be present in some women based on food habits.

In infection

In infection, the vaginal odour is associated with different symptoms that are specific to the type of infection. A rotten fish-like odour may also be present in the case of a bacterial infection such as bacterial vaginosis.

Causes

Causes of  different types of vaginal odour include:

  • Hormonal changes
    Changes in the levels of progesterone and oestrogen hormones from the onset of the menstrual cycle to its end are responsible for the changes in the odour of the vaginal discharge during that period.
    Women on oral contraceptive pills usually do not experience changes in vaginal odour during their monthly cycle.
  • Infections
    Foul vaginal odour occurs in the case of an infection in the cervix and vagina. Infection caused by bacteria, yeast or fungi, viruses and parasite generally give rise to a foul vaginal odour. Some of these infections are:
    • Bacteria vaginosis
      A thin and watery vaginal discharge that smells like fish or has an unpleasant smell is commonly associated with bacterial vaginal infection (bacterial vaginosis).
    • Candidiasis
      Vaginal discharge due to a fungal infection does not have a very strong smell. Fungal or yeast infection in the vagina (by Candida albicans) causes a thick white and lumpy discharge like cottage cheese. It is also associated with intense itching and soreness in the vagina.
    • Trichomoniasis
      Infection in the vagina due to parasites such as Trichomonas vaginalis is known as trichomoniasis and it causes a foul-smelling vaginal discharge. The discharge appears like froth and is yellow or green in colour.
    • Chlamydia and Gonorrhoea
      Bacteria such as Chlamydia trachomatis and Neisseria gonorrhoea cause sexually transmitted infections namely chlamydia and gonorrhoea. These bacterial infections commonly result in a strong smelling thick yellow discharge with severe burning sensation while passing urine. Vaginal bleeding in between menstrual periods is a common symptom of chlamydia and gonorrhoea infection.
  • Pelvic inflammatory disease
    Pelvic inflammatory disease or chronic inflammation of the reproductive organs due to untreated bacterial infections usually results in a chronic, mild, and unpleasant smelling vaginal discharge along with a dull pain in the lower abdomen and genital region.
  • Delivery
    Lochia or bleeding from the uterus for 4 to 5 days post-delivery results in foul vaginal odour.
  • Genetic disorders
    A rare genetic condition called primary trimethylaminuria results in vaginal odour that smells like rotten fish.
  • Menopause
    Women in menopause develop vaginal dryness and irritation. This sometimes results in foul vaginal odour.
  • Cancer
    Infection in case of a tumour or cancer in the uterus or cervix results in a foul-smelling vaginal discharge.

Risk factors

In a majority of cases, infection is the cause of unpleasant vaginal odour. Factors that increase the risk of infections are also the chief risk factors for foul vaginal odour. Vaginal odour due to factors related to normal body functions (ovulation, menstruation, pregnancy, and post-delivery) is normal.

  • Lack of hygiene, sexual intercourse with an infected partner, using public toilets, douching, diabetes, and other such conditions are some of the most common risk factors for a vaginal infection.
  • Change in the acidic environment or the pH of the vagina favours the growth of infectious organisms. Some products that may cause vaginal pH imbalance are scented wipes or sprays for cleaning the vagina or douching, long-term intake of antibiotics, among others.
  • Pregnancy increases the risk of yeast infection in the vagina, which results in a cottage cheese-like vaginal discharge with a mild foul odour.
  • Menopause
  • Women undergoing radiation therapy for cancer of the cervix or uterine cancer are at high risk of developing a foul-smelling vaginal discharge.

The following steps can help prevent the conditions that result in foul vaginal odour:

  • Maintain adequate hygiene in the genital area. (Read more: Tips on keeping your vagina healthy)
  • Use front to back (genital region to anus) washing method to keep the genital area clean in order to prevent vaginal infections.
  • Do not douche or wash the vagina with perfumed gels, wipes, or sprays, as these increase the risk of infection by decreasing the acidity of the vagina. (Read more: How to wash your vagina)
  • Clean the area around your vagina with a pH balanced soup only once a day while taking a shower and also, after sexual intercourse.
  • Do not wear tight-fitting undergarments.
  • Doctors advice douching only in case a woman is undergoing internal radiation therapy for the treatment of cancer in the uterus or the cervix.
  • To prevent primary trimethylaminuria, dietary changes help largely. These include avoiding eggs, milk, beans, peanuts, food items containing lecithin, and more.
  • Keep sweat under control by wearing cotton underwears, frequent bathing, and avoiding panties made of silk or polyester fabric.

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Doctors diagnose foul odour from the vagina on the basis of the woman’s history of the symptoms, physical examination, and laboratory investigations.

History of symptoms include:

  • The onset of the symptoms.
  • Menstrual history.
  • Sexual history.
  • Personal hygiene habits and contraceptive methods (frequent douching, allergy to vaginal diaphragm or condom, use of a tampon, etc.)
  • Diet history.
  • Medical history to consider the presence of conditions like diabetes, cancer, and more.

Physical examination

Physical examination of the vagina and the cervix using different instruments helps the doctor to diagnose the cause of the malodorous discharge.

Lab tests

Lab tests help in confirming the diagnosis or the cause of abnormal vaginal odour. These tests include:

  • Microscopic examination
    A sample of vaginal discharge is mixed with warm saline water or a chemical called 10%  sodium hydroxide solution and is examined under the microscope to identify the organisms (bacteria, yeast, and protozoa) responsible for infection and specific vaginal odour.
  • pH test
    Testing the pH (using pH testing litmus paper) of the discharge helps in the diagnosis of the type of organism causing the infection. For example, pH of the vaginal discharge due to fungal infection is less than that caused by bacteria and Trichomonas (parasite).
  • Whiff test
    A sample of vaginal discharge mixed with 10% potassium hydroxide solution results in a foul odour (amine) when bacteria is the causative agent.

Few other tests that are also used for diagnosing the cause of the abnormal smell and discharge from the vagina include:

  • Culture test
    Used for fungal infections in the vagina.
  • DNA probe
    BD< affirm VPIII is a test that identifies Candida, Trichomonas, and Gardnerella very quickly.
  • Rapid antigen test
    OSOM TV for detecting Trichomonas.
  • Nucleic acid amplification tests or NAAT
    It is used for detecting the genetic material of the suspected virus or bacteria.
  • PIP activity
    Proline aminopeptidase activity is a test to diagnose bacterial vaginosis.
  • BV-Blue
    This test detects the vaginal discharge for elevated levels of the enzymes produced by disease-causing bacteria.
  • PCR
    Polymerase chain reaction (PCR) for detection of organisms causing sexually transmitted diseases like gonorrhoea.

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Treatment of the underlying cause plays a key role in the management of vaginal odour.

Medical treatment

  • Antibiotics such as metronidazole, clindamycin, clotrimazole, etc. and antifungal drugs in the form of oral tablets, suppository, and cream, depending on the severity of the symptoms, are used for the treatment of infection. Infection usually resolves in 5 to 7 days with proper treatment. However, it is necessary to monitor the symptoms for one month as the rate of recurrence or relapse of infection is very high in the case of bacterial and fungal infections. (Read more: Precautions to take with antibiotics)
  • A short course of antibiotics helps to decrease the production of trimethylaminuria in the intestines, which helps in reducing the vaginal odour.
  • Supplements containing charcoal or vitamin B2 help in reducing the foul odour from the vagina and rest of the body due to primary trimethylaminuria to some extent.

Self-care measures

  • Treating both partners is essential in the management of sexually transmitted diseases.
  • Maintaining adequate hygiene plays a key role in the management of vaginal odour without a pathological cause.

Lifestyle management

Vaginal odour is a stressful condition that can make the woman feel uncomfortable socially and also causes psychological disturbances. Few lifestyle management methods help in preventing/lowering the risk of developing a vaginal odour. These include:

  • Avoid consuming alcohol while taking antibiotics for the treatment of vaginal infection.
  • Abstain from sexual activity during the treatment period.
  • Wash the genital area with a pH balanced mild soap and water only once a day to keep it clean.
  • Keep the genital area clean and dry.
  • Do not wash the vagina or douche with soap water, perfumed scrubs, gels, etc. Avoid using perfumed sprays and deodorants in the vaginal area.
  • Follow front to back (from the vagina to the anal region) washing technique to prevent the infectious organisms from the rectum to enter the genital area.
  • Wear clean and washed undergarments.
  • Use cotton inner wears instead of tight-fitting polyester or silk ones.
  • In the case of primary trimethylaminuria, avoid lecithin-rich food items (cow milk, eggs, peanuts, and others) and heavy exercises to control sweating.
  • Manage stress by practising meditation to stay calm, as stress increases sweating, causes hormonal imbalance and intensifies the odour of body secretions. (Read more: Meditation for stress relief)

Prognosis

Vaginal odour due to an infection generally resolves after completing the antibiotic course. Foul odour from vaginal and other body secretions resulting from primary trimethylaminuria, a genetic disorder, is incurable. Certain lifestyle management measures help in controlling the bad odour but do not cure it. Odours associated with the type of dietary intake usually resolve by limiting their consumption.

Complications

Relapse or reinfection resulting in foul vaginal odour is frequently the most common complication. Diabetes, pregnancy, and poor immunity are some common conditions that are responsible for the relapse of yeast (thrush or candidiasis) and bacterial infections of the vagina.

References

  1. Min Li et al. Fish odour syndrome . CMAJ. 2011 May 17; 183(8): 929–931. PMID: 21422137
  2. Doty RL et al. Changes in the intensity and pleasantness of human vaginal odors during the menstrual cycle. Science. 1975 Dec 26;190(4221):1316-8. PMID: 1239080
  3. Center for Disease Control and Prevention [internet], Atlanta (GA): US Department of Health and Human Services; Vaginitis
  4. National Health Service [Internet]. UK; Vaginal discharge.
  5. National Health Service [Internet]. UK; Your body just after the birth.
  6. Gordon N. Semen responsible for fishy vaginal odor. J Fam Pract. 1995 Jun;40(6):538, 540. PMID: 7775904
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