How bacterial vaginosis develops and how it differs from vaginal thrush.
What is bacterial vaginosis?
Bacterial vaginosis is the most common vaginal infection amongst women of reproductive age. Nevertheless, it is frequently not recognised or is misdiagnosed as a vaginal yeast infection. The condition is caused by an imbalance of the vaginal flora, in which certain bacteria multiply excessively and displace the healthy lactic acid bacteria (lactobacilli). Consequently, this alters vaginal discharge and an can cause an unpleasant intimate odour.
Apothekerin
DR. KADE
Medical Affairs
What will be discussed
Causes of an imbalance of the vaginal flora
A healthy vagina has a stable vaginal flora. This flora consists primarily of lactic acid bacteria, lactobacilli, which maintain an acidic environment (pH value 3.8 to 4.5). In this acidic environment, disease-causing germs have little chance of multiplying.
However, if dysbiosis occurs, an imbalance of the natural vaginal flora, the Gardnerella vaginalis bacterium can spread particularly quickly. This bacterium is a typical cause of bacterial vaginosis and displaces the lactobacilli, thereby destabilising the vaginal environment.
Common causes and risk factors
- Hormonal changes
- Excessive or poor intimate hygiene, for example aggressive washing lotions, intimate deodorants or vaginal douches
- Sexual activity, particularly frequent changes of sexual partners or anal-to-vaginal intercourse without changing the condom
- Smoking
- Psychological stress
- Incorrect wiping technique after a bowel movement (wiping from back to front instead of front to back)
- Use of shared sex toys without adequate cleaning.
When the vaginal environment is out of balance or intimate complaints occur more often, bacterial vaginosis can develop more easily. In some cases, the infection can even spread upwards and cause inflammation, such as cervicitis (inflammation of the cervix) or salpingitis (inflammation of the fallopian tubes). Early medical treatment is therefore important and usually requires antibiotics. Targeted restoration of the vaginal flora afterwards can help to prevent relapses.
Symptoms: How to recognise bacterial vaginosis
The symptoms of bacterial vaginosis can vary greatly. While some women experience unpleasant and distressing symptoms, others hardly notice any symptoms or have none at all. If symptoms occur, they mainly include:
- Increase in watery, grey-white or foamy vaginal discharge
- A fishy intimate odour that may worsen after sexual intercourse or during menstruation and cannot be washed away
- An increased vaginal pH value (> 4.5)
While itching is less common in bacterial vaginosis, some women experience burning or irritation in the external genital area. A characteristic feature distinguishing it from vaginal thrush is the odour in combination with the consistency of the discharge. While fungal infections are often accompanied by itching and a crumbly white discharge, bacterial vaginosis usually does not cause the distressing itching at the vaginal opening.
Many affected individuals completely lack the typical symptoms. Instead, bacterial vaginosis may be noticeable through frequent or recurring urinary tract infections, irritable bladder symptoms or non-specific discharge.
Comparison: Bacterial vaginosis vs vaginal thrush
| Bacterial vaginosis |
Vaginal thrush |
|
| Discharge | greyish-white, watery |
whitish-crumbly |
| Odour | unpleasant to fishy |
odourless |
| Itching / burning | possible in the external genital area | severe itching and burning at the vaginal opening |
| Vaginal pH value | > 4,5 | usually normal |
Diagnosis: how bacterial vaginosis is diagnosed
If bacterial vaginosis is suspected, a gynaecological examination is recommended. During this examination, it can usually be determined quickly whether it is indeed bacterial overgrowth or another type of vaginal infection.
Key components of clinical diagnosis:
- Visual diagnosis: The appearance of the mucous membrane and the discharge alone can already give clues to bacterial vaginosis, such as the typical grey-white, watery discharge
- Medical history: The doctor will ask about your symptoms, any odour, discharge and whether the symptoms have occurred before
- Measurement of the pH value: A pH value above 4.5 suggests bacterial vaginosis, but is only meaningful when considered along with other symptoms.
- Microscopic smear: So-called clue cells can be detected, which are vaginal cells densely covered with bacteria.
- Amine test (whiff test): If the odour is not immediately apparent, an amine test can be performed. In this test, a potassium hydroxide solution is added to a vaginal swab. The development of a fishy odour indicates bacterial vaginosis.
- Nugent score: A special lab test in which the bacterial composition of the swab is precisely assessed.
Important: An elevated pH level can also occur in other vaginal infections. The diagnosis is therefore always based on a combination of several symptoms.
Bacterial vaginosis cannot be reliably self-diagnosed and should not be confused with vaginal thrush, as the treatment is completely different.
In some cases, an additional test for sexually transmitted diseases (STIs) is advisable – especially if the symptoms are unclear or recurrent. Bacterial vaginosis can be mistaken for STIs or occur at the same time.
Frequency and course of bacterial vaginosis
Many women experience at least one episode of bacterial vaginosis during their lifetime. The risk is particularly high during reproductive years.
In many cases, the infection is mild or goes unnoticed. However, if it is not recognised or treated consistently, it can recur. Relapses are common even after antibiotic treatment. This is partly due to the formation of a biofilm.
Certain bacteria, especially Gardnerella vaginalis, accumulate in a protective biofilm on the vaginal wall. This biofilm makes it difficult for antibiotics to reach and completely eliminate all bacteria. This perpetuates a bacterial imbalance – and the symptoms often return after a short time.
In vielen Fällen verläuft die Infektion mild oder bleibt unbemerkt. Wird sie jedoch nicht erkannt oder nicht konsequent behandelt, kann sie immer wiederkehren. Auch trotz antibiotischer Therapie kommt es häufig zu Rückfällen – der Grund dafür ist die Bildung eines sogenannten Biofilms:
Bestimmte Bakterien, vor allem Gardnerella vaginalis, lagern sich in einem schützenden Biofilm an der Scheidenwand ab. Dieser Biofilm erschwert es dem Antibiotikum, alle Keime zu erreichen und vollständig zu beseitigen. Dadurch bleibt ein bakterielles Ungleichgewicht bestehen – und die Symptome kehren oft nach kurzer Zeit zurück.
Bacterial vaginosis during pregnancy
During pregnancy, the vaginal environment is particularly sensitive. Hormonal changes and an altered immune system can increase the risk of bacterial vaginosis.
Possible consequences of an untreated infection:
- Premature labour
- Premature water breaking
- Premature birth or miscarriage
When bacterial vaginosis is detected early, effective treatment with locally applied antibiotics is possible, including options that are approved for use during pregnancy.
Lactic acid preparations do not replace antibiotic treatment, but they can help support the natural vaginal balance.
The KadeFlora Lactic Acid Treatment (KadeFlora Milchsäurekur) and the KadeFlora Lactic Acid Ovules (KadeFlora Milchsäureovula) are suitable for use during antibiotic treatment to restore the acidic environment and support the regeneration of the natural vaginal flora.
Following antibiotic treatment, KadeFlora Lactic Acid Bacteria Ovules (KadeFlora Milchsäurebakterien Vaginalkapseln) help rebuild the vaginal flora.
For infection prevention, lactic acid treatments or lactic acid ovules may be used regularly for 2–3 days per month, for example after menstruation, to support the vaginal environment and reduce the risk of recurrent infections.
If a pregnancy is planned, the vaginal balance should ideally be strengthened prior to conception.
Avoiding recurrent bacterial vaginosis
Many women experience not only one episode, but repeated relapses. In many cases, this is because the natural vaginal flora has not sufficiently recovered after treatment.
To reduce the risk of recurrent bacterial vaginosis, it is important to strengthen the intimate area in a targeted way. Products that support the vaginal flora can be beneficial, such as:
- Lactic acid gels or ovules (vaginal suppositories) that regulate and stabilise the pH value
- Vaginal ovules with probiotic lactic acid bacteria that restore bacterial balance
Learn more about supportive treatment and suitable KadeFlora products on our page about the treatment of bacterial vaginosis.
Is bacterial vaginosis contagious?
No, bacterial vaginosis is not a classic sexually transmitted infection (STI) and is not considered to be directly contagious. However, it can be transmitted or exacerbated in the context of certain sexual practices or poor hygiene – especially if the vaginal environment is already imbalanced.
Possible indirect routes of transmission:
- Unprotected sex or frequent changes of sexual partners
- Poor hygiene when using sex toys
Can partners become infected?
Male partners usually do not develop symptoms and generally do not require treatment. In lesbian relationships or in cases of frequent relapses, joint treatment may be advisable – please discuss this with your gynaecologist.
Conclusion: Bacterial vaginosis is not directly contagious but can be exacerbated or triggered again by certain circumstances. Preventive measures such as condom use, good hygiene and protection of the vaginal flora are therefore especially important.
Preventing bacterial vaginosis
A stable vaginal flora is the best protection against a bacterial vaginal infection. These tips can help prevent bacterial infections in the vagina.
- Avoid using vaginal douches, scented intimate deodorants or harsh wash gels
- Clean your intimate area using only pure water or a special intimate wash lotion
- Always wipe from front to back after a bowel movement
- Use condoms during sex – especially when trying different positions
- Reduce stress and promote physical activity
- Healthy diet
- Use KadeFlora Lactic Acid Treatment (KadeFlora Milchsäurekur) or KadeFlora Lactic Acid Ovules (KadeFlora Milchsäureovula) regularly for 2–3 days – e.g., after your period
FAQ Frequently asked questions about bacterial vaginosis
Bacterial vaginosis is usually harmless and can be treated effectively. In rare cases, however, untreated bacterial vaginosis may lead to spreading of the infection, such as inflammation of the cervix or the fallopian tubes. During pregnancy, untreated bacterial vaginosis can increase the risk of premature birth. Early diagnosis is therefore important.
Although both conditions affect the genital area, they differ significantly in their causes and symptoms:
Bacterial vaginosis typically presents with a watery, greyish-white discharge with a fishy odour and usually without itching.
In contrast, vaginal thrush often causes a white, crumbly discharge along with itching, burning and redness of the mucous membrane. The pH value is also different: In bacterial vaginosis, the pH is usually above 4.5, whereas in vaginal thrush it is normal.
The treatment of bacterial vaginosis depends on the severity of the symptoms and on whether it is a first-time or recurrent infection. In most cases, treatment requires antibiotics that target the bacteria causing the infection.
However, since antibiotics can also reduce the protective lactic acid bacteria in the vagina, it is important to:
- use lactic acid treatment alongside antibiotic treatment
- use probiotic lactic acid bacteria as ovules during and/or after antibiotic treatment. These help to restore the natural balance of the vaginal flora and prevent recurrence.
In cases of known, mild symptoms, treatment with lactic acid preparations alone may also be an option – for example with KadeFlora Lactic Acid Treatment (KadeFlora Milchsäurekur) or KadeFlora Lactic Acid Ovules (KadeFlora Milchsäureovula).
An accurate diagnosis is important to determine the appropriate treatment. You can find more information on our treatment page for bacterial vaginosis.
No – a reliable diagnosis is important to rule out other possible causes, such as vaginal thrush or a sexually transmitted infection.
Lactic acid preparations from the pharmacy can help support the vaginal flora, but they do not replace a medical check-up. If discharge persists or keeps recurring, you should always consult a gynaecologist.
Bacterial vaginosis is not a classic sexually transmitted disease and is not considered to be directly contagious. Nevertheless, it can be exacerbated by certain sexual practices – such as unprotected sex, frequently changing partners, or switching from anal to vaginal intercourse without a condom.
Male partners usually show no symptoms and do not need treatment. In same-sex relationships or when relapses occur frequently, treating both partners under medical guidance may be advisable.
Bacteria of the species Gardnerella vaginalis are often the cause of bacterial vaginosis. These bacteria are usually found in the gut. They can easily travel from the gut to the vagina through smear infection.
This can happen e.g., if you wipe back to front after a bowel movement. The bacteria can also easily cross the short distance from the gut to the vagina during sex. This sometimes happens when the penis is inserted into the vagina, but the risk is particularly high when switching from anal to vaginal intercourse. To prevent vaginal infections, you should always change the condom when using this method.
