1. Hall, Susan EdD, MSN, RNC, CCE


Find out the facts about one of the most common vaginal conditions among female patients of childbearing age.


Article Content

A loss of balance between good and bad bacteria in the vagina results in the growth of anaerobic bacteria such as Gardnerella vaginalis, resulting in a condition known as bacterial vaginosis (BV). According to a 2015 CDC update, "BV is a polymicrobial clinical syndrome resulting from replacement of the normal hydrogen peroxide producing Lactobacillus species in the vagina with high concentrations of anaerobic bacteria (such as Prevotella species and Mobiluncus species), G. vaginalis, Ureaplasma, Mycoplasma, and numerous fastidious or uncultivated anaerobes." This condition is associated with unusual vaginal discharge and increases the risk of contracting sexually transmitted infections (STIs).

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About 30% of women in the United States have BV during their pregnancies, according to the CDC. BV is a dangerous condition in pregnant women because it's associated with low birthweight, premature birth, miscarriage, endometritis, chorioamnionitis, and neonatal meningitis. BV is also one of the causes of pelvic inflammatory disease (PID). If PID isn't detected and treated early, the risk of infertility or ectopic pregnancy increases.


Risk factors

All women who've ever had a miscarriage or a low birthweight or premature birth should be tested for BV. Also, women who are planning an abortion or hysterectomy should be tested for BV because they're at increased risk for contracting this condition following a surgical procedure. Douching is another risk factor for BV because it can disturb the normal balance of bacteria in the vagina; women who douche should undergo a clinical test for BV. Other predisposing risk factors for BV include engagement in early sexual activity, promiscuity, previous STIs, previous vaginal discharge, and previous spontaneous abortion.


Diagnosis and treatment

Although it isn't unusual for women to experience normal vaginal discharge during pregnancy, an abnormal discharge calls for examination. In most cases, patients with BV experience cloudy vaginal discharge with or without odor. Some patients may experience burning when urinating and/or itching around the outside of the vagina. Further clinical examination of the discharge may reveal a pH above 4.5. BV is typically present if adding 10% potassium hydroxide to the discharge produces a strong fishy odor (whiff test). Furthermore, an examination of the discharge will reveal a layer of clue cells (coccobacilli). The clinician may conduct more than one of these observations to ascertain the existence of BV.


BV is diagnosed by a gram stain of a vaginal smear (Nugent score of 7 to 10) in combination with clinical findings that infection is present.


Although abnormal vaginal discharge is the best indicator of BV, most women are asymptomatic or experience odorless discharge; thus, they may not be aware that they have BV. Various studies have shown that over 63% of patients who test positive for BV are asymptomatic; over 35% of pregnant women with BV experience clear and odorless vaginal discharge.


Treatment for BV includes antibiotic therapy, such as oral metronidazole or metronidazole gel applied intravaginally. Instruct patients to avoid alcohol 12 hours before treatment with metronidazole, during treatment, and 24 to 48 hours after treatment.


Screen queen

BV resolves itself without treatment in most women. However, clinical testing and treatment are needed for pregnant women because of associated risks, such as low birthweight, premature birth, and miscarriage. Most pregnant women are asymptomatic and may have a normal discharge, thus making it hard to establish the presence of this condition. Therefore, it's appropriate for all pregnant women to undergo testing for BV during a regular clinical visit as a preventive measure.




Acton A. Bacterial Vaginosis: New Insights for the Healthcare Professional. ScholarlyEditions; 2013.


American Pregnancy Association. Bacterial vaginosis during pregnancy.


CDC. 2015 sexually transmitted diseases treatment guidelines: bacterial vaginosis.


CDC. Bacterial vaginosis (BV) statistics.


Germain A, Holmes KK, Piot P, Wasserheit J. Reproductive Tract Infections: Global Impact and Priorities for Women's Reproductive Health. New York, NY: Springer Science & Business Media; 2013.


Marconi C, Duarte MT, Silva DC, Silva MG. Prevalence of and risk factors for bacterial vaginosis among women of reproductive age attending cervical screening in southeastern Brazil. Int J Gynaecol Obstet. 2015;131(2):137-141.