Bacterial Vaginosis: Symptoms, Risk & Treatment
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Bacterial Vaginosis: Symptoms, Risk & Treatment

Bacterial vaginosis causes symptoms that are different from those of the other two types of the common vaginal infection or the one with Trichomonas. It is possible to have more than one type of vaginal infection at the same time. It is often confused with yeast infection (candidiasis), or infection with Trichomonas vaginalis (trichomoniasis), which are not caused by bacteria.

Bacterial vaginosis causes symptoms that are different from those of the other two types of the common vaginal infection or the one with Trichomonas. It is possible to have more than one type of vaginal infection at the same time. It is often confused with yeast infection (candidiasis), or infection with Trichomonas vaginalis (trichomoniasis), which are not caused by bacteria.

Bacterial vaginosis is a change in the balance of the bacteria that are normally present in the vagina, which can lead to troublesome symptoms. Bacterial vaginosis is the most common cause of vaginal symptoms in women of childbearing age.


The most important symptom of bacterial vaginosis is the elimination of excessive discharge, bad-smelling, white-gray, different from the normal vaginal discharge. One in three women with bacterial vaginosis describes a yellow discharge.

An upsetting "fish" or onion smell, which usually gets stronger after sex, is the alarm signal of bacterial vaginosis.

However, almost half of women with bacterial vaginosis have no symptoms that would drag attention.

Bacterial vaginosis is not necessary to determine the occurrence of itching (pruritus)!

Other conditions that may present similar symptoms are sexually transmitted diseases, urinary tract infection and vaginal infection.

What are the risks associated with bacterial vaginosis?

Bacterial vaginosis is especially important if the woman is pregnant. During pregnancy, it can lead to the occurrence of complications such as:


-premature (preterm)

-pelvic infection - after birth.

Uterine infection is a common cause of premature birth - bacterial vaginosis can cause this type of infection or may be a warning sign of another problem that can cause premature birth. Experts continue to investigate if bacterial vaginosis is caused directly or indirectly.

The presence of bacterial vaginosis when a procedure / pelvic invasive techniques (such as birth by cesarean section, hysterectomy, abortion or placement of an intrauterine device), increases the risk of a pelvic infection.

The presence of bacterial vaginosis at the time of exposure to a sexually transmitted disease (including HIV) increases the risk of infection.


Bacterial vaginosis is caused by a loss of balance in the vaginal flora. Normally, about 95% of the vaginal flora is formed by a bacteria called lactobacillus. They help maintain the pH low preventing the overgrowth of other types of microorganisms.

What exactly causes bacterial vaginosis is unknown. However, a number of known risk factors causes changes to the normally existing bacterial flora in the vagina: a decrease of lactobacilli and an increase of the bacteria that are less "friendly", whose breeding is usually kept under control by higher levels of lactobacilli. Thus women with bacterial vaginosis have fewer lactobacillus organisms type than normal and several other bacteria.

These risk factors include sexual activity, presence of STDs in the past, excessive intravaginal washing, vaginal tampons, diaphragms and intrauterine device use.

Bacterial vaginosis is more common in women who have multiple sex partners or having a woman as a sexual partner.

Bacterial vaginosis is sometimes influenced by hormonal changes and this is more common around the time of menstruation and occurs in up to 23% of pregnant women.

Risk factors

Factors that increase the risk of bacterial vaginosis include:

- Early sexual life

- Sexually transmitted disease

- Multiple sex partners

- A female sexual partner

- Use of intrauterine devices

- The use of pads or diaphragm

- Excessive vaginal washes

- Oral-genital sexual activity.

Although bacterial vaginosis appears to be triggered or worsened by sexual contact, it is not sexually transmitted disease. 

Bacterial vaginosis can be difficult to differentiate from other types of vaginal infection.


Bacterial vaginosis is diagnosed based on symptoms, a pelvic exam and a microscopic examination of samples from vaginal discharge.

When at the microscope there is a small number of lactobacilli and a greater number of other bacteria, the diagnosis is of bacterial vaginosis.

Going to see a specialist is a must when:

- There is a low abdominal pain and fever higher than 38.3degrees C, associated with smelly (or not) vaginal discharge

- Symptoms of vaginal infection during pregnancy .

A medical checkup within a week if:

- Any unusual vaginal discharge that has an odor, especially after sex

- Any unusual vaginal itching

- Pain during intercourse or pain after urination (dysuria)

- Discomfort or discharge that might indicate the presence of vaginal infections.

Watchful waiting

It is generally recommended to consult or contact a doctor about the vaginal symptoms you have.

The only exception to this rule is when you are sure that your vaginal symptoms indicate a vaginal infection(if you had a vaginal infection before and now you are sure you have a vaginal infection rather than bacterial vaginosis). If your symptoms are due to a sexually transmitted disease and not bacterial vaginosis, your sexual partner can be infected as well if you delay treatment. Also more serious complications can occur due to sexually transmitted diseases such as pelvic inflammatory disease.

It is recommended to:

- Avoid any sexual contact before being seen by a doctor, this will prevent a possible spread of STDs

- Avoid douching, unless your doctor agrees.

Laboratory Investigations:

The doctor may perform a test for bacterial vaginosis if you:

- have symptoms

- are going to do a hysterectomy or surgical abortion (bacterial vaginosis increases the risk of infection after their performance)

- are pregnant and you have had a premature birth - a premature birth in the past could have been caused by infection.

Your doctor can diagnose bacterial vaginosis based on your symptoms, vaginal exam and a sample of vaginal discharge.

Laboratory tests that detect signs of bacterial vaginosis may include:

- "Wet mount". A sample of vaginal discharge is placed on a microscope slide and then mixed with a saline solution (normosalina).

The prepared slide is examined carefully to:

- identify the present bacteria,

- search for white blood cell (WBC) which indicates the presence of infection

- look for unusual cells which are called key cells. These clue cells are the most reliable indicators of bacterial vaginosis.

- Whiff test. A few drops of potassium hydroxide (KOH) is added to a sample of vaginal discharge and follow if it produces a strong fishy odor (onion odor). If the odor occurs, this suggests the presence of bacterial vaginosis.

- Vaginal pH. Normal vaginal pH is 3.8 - 4.5. Bacterial vaginosis often causes an increase in vaginal pH over 4.5.

- Performing cultures. Making a culture of vaginal discharge may show a significant multiplication of Gardnerella vaginalis, which may be associated with bacterial vaginosis.

- Pap test (Papanicolaou test). Bacterial vaginosis can be detected during a routine Pap test. However, the Pap test is a standard test for diagnosis of bacterial vaginosis.

- Gram stain. A sample of vaginal discharge is placed on a microscope slide. A special stain is applied to the slide, and therefore some types of bacteria (Gram-positive bacteria) is colored in purple, while others (Gram-negative bacteria) is colored in pink. In bacterial vaginosis, Gram - negative, especially Gardnerella vaginalis, are very common.

- Samples with oligonucleotides. This test detects genetic material (DNA) of bacteria in bacterial vaginosis. Oligonucleotides test is very accurate but cannot be performed routinely in most laboratories.


Bacterial vaginosis spontaneously disappears without treatment in 25% of people, so treatment is not always necessary.

Bacterial vaginosis is treated with antibiotics. Metronidazole (Flagyl) is the treatment of first intention. If the person concerned is not pregnant, take medication orally (pills), or intravaginal insert. Pregnant women can be treated only orally.

Antibiotic treatment for bacterial vaginosis can cause vaginal infections because the drugs alter the balance of microorganisms in the vagina, allowing infection to develop in excess vaginal. This can be avoided by eating yogurt with active cultures regularly by Lactobacillus acidophilus or if supplements are taken with L. acidophilus.

Some women can be successfully treated using oral or vaginal lactobacillus.

Treating the sexual partner is not helpful, because bacterial vaginosis is not caused by a sexually transmitted microorganism.

Current treatment options for bacterial vaginosis include:

- Watchful Waiting. Approximately 25% of women with bacterial vaginosis will cure themselves on their own. This happens when the vaginal lactobacilli organisms multiply tending to reach their normal level and the other bacteria begins to drop.

- Antibiotics (oral or intravaginal). Antibiotics can kill the bacteria that causes bacterial vaginosis symptoms but sometimes doesn`t solve the fundamental cause. Therefore, bacterial vaginosis symptoms recur in about 30% of women after treatment with antibiotics.

- Restoration of lactobacilli inside the vagina using yogurt or dietary supplements.

Bacterial vaginosis in itself is not a serious medical condition and often disappears without treatment. In practice, approximately 50% of women who were tested positive for bacterial vaginosis have no symptoms. However, during pregnancy, surgery or vaginal invasive procedures, bacterial vaginosis makes the reproductive tract vulnerable to infection or inflammation, which can then lead to the emergence of various problems such as premature birth and pelvic inflammatory disease. Therefore, the doctor will do tests for bacterial vaginosis diagnosis and recommend treatment for women who:

- have persistent symptoms

- are pregnant and have symptoms of bacterial vaginosis

- are pregnant and have symptoms of bacterial vaginosis, but previously had a preterm birth (earlier than 37 weeks of pregnancy) which could be caused by an infection

- are going to have a hysterectomy or surgical abortion. Administration of antibiotics for bacterial vaginosis before hysterectomy or surgical abortion significantly reduces the risk of developing a severe infection afterwards.

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