Bacterial Vaginosis

What is bacterial vaginosis?

Bacterial vaginosis (BV) is the most common cause of vaginal discharge in women during their reproductive years; it is more common than “thrush”.

Some studies indicate that up to 30% of women are affected

The discharge has a fishy odour, which is intensified after intercourse and during menstruation. Itching and soreness are not features of BV. In 1983 the condition was called bacterial vaginitis but inflammation of the vagina is not a feature and it was renamed vaginosis. There have been other names including non specific vaginitis, haemophilus vaginitis and non specific vaginosis.

In 1983, Amsel and colleagues noted that numerous previous studies of nonspecific vaginitis had yielded contradictory results regarding its cause and clinical manifestations, due to a lack of uniform case definition and laboratory methods. They studied 397 consecutive unselected female university students and applied sets of well defined criteria to distinguish nonspecific vaginitis from other forms of vaginitis and from normal findings. Using such criteria, we diagnosed nonspecific vaginitis in up to 25 percent of our study population; asymptomatic disease was recognized in more than 50 percent of those with nonspecific vaginitis. Gardenerella vaginalis was isolated from 51.3 percent of the total population using a highly selective medium that detected the organism in lower concentration in vaginal discharge than did previously used media.

Although bacteria and therefore infection, underlie this condition, inflammation is not seen and therefore the term vaginitis, which implies inflammation was deemed to be inappropriate. In the early ’80s the term vaginosis was popularised and we now call the condition bacterial vaginosis.

In women with recurrent BV, BV arises most often around the time of menstruation and resolves spontaneously in mid-cycle. Recurrences often follow an episode of candidiasis, and BV often regresses after unprotected sexual intercourse.


A typical finding with bacterial vaginosis is a reduction in the number of the protective lactobacilli.

Another typical feature is the presence of “Clue cells”.

Picture of Clue Cells –

Clue cells are vaginal surface cells (epithelial cells) that are surrounded by numerous bactieria as seen on gram staining of the vaginal discharge.

Mode of transmission

Sexual transmission of BV does not seem to be a factor.

A variety of microorganisms have been implicated but we still do not know which are the main culprits. Attention has focused on a bacterium named Gardnerella vaginalis. This organism can be found in more than 50% of healthy women. A thousand-fold increase in concentration of Gardnerella and other anaerobes (bacteria that can thrive at low oxygen levels) is typical of BV. Some suggest that BV is a sexually transmitted condition. Bacterial vaginosis, however, can occur in virgins. Diagnosis is made essentially from the history and the nature of the discharge, which has a typical pattern on direct microscopic examination. Swabs sent for culture are not helpful.

Bacterial vaginosis is likely to occur when the balance between protective organisms (lactobacilli) and potential pathogens (organisms associated with disease) is adversely altered. Excessive vaginal douching, for example, may lead to bacterial vaginosis by removing the lactobacilli. Semen reduces the natural acidity of the vagina and predisposes to BV.

Bacterial vaginosis is more common among black Caribbean than white women (OR, 2.1; 95% CI, 1.1-4.1). Vulval use of bubble bath or antiseptic solutions and douching with proprietary or homemade solutions is significantly more common in women with bacterial vaginosis than without. After controlling for use of vulval and vaginal antiseptics and bubble bath, douching, and a history of bacterial vaginosis, there is no ethnic difference in the occurrence of the condition.

Treatment of Bactieral Vaginosis

Metronidazole has been shown to be effective.

Lactic acid restores natural vaginal acidity and has been shown to treat and prevent bacterial vaginosis.

Lactic acid gel has become available in gel format from December 2008 as Relactagel.

Associated Complications

There have been suggestions that BV may be a factor in miscarriage and premature delivery and studies are under way to investigate the potential benefit of antibiotic treatment.

It has been shown that treatment of bacterial vaginosis my potentially reduce some cases of premature delivery.

David Viniker, the author of this website has introduced the hypothesis that sub-clinical bacteria could provide a plausible explanation for several obstetric and gynaecological enigmas including unexplained infertility, recurrent miscarriage, dysfunctional uterine bleeding and blood pressure problems (preeclampsia) associated with pregnancy.  Others have more recently come to a similar conclusion with regards to preeclampsia. A great deal of research will be required to investigate this concept as these conditions probably result from a variety of causes, which will confound analysis. At this time we do not know whether antibiotics will prove to be of value.


How is bacterial vaginosis treated?

Bacterial vaginosis (Q 22.7) responds to antibiotics active against anaerobic bacteria. Oral metronidazole?(Flagyl – Hawgreen) tablets two or three times daily have been the traditional first line of treatment. Clindamycin (Dalacin – Pharmacia and Upjohn) vaginal cream introduced each night for a week and metronidazole gel (Zidoval – 3M Health Care) one application for five nights have provided further options. Some women are prone to recurrence; there is no evidence that treating the partner provides benefit.


Support Groups

Members of a support group, provide each other with various types of help and information for a particular shared difficulty.

The support may take the form of providing relevant information,

  • relating personal experiences,
  • listening to others’ experiences,
  • providing sympathetic understanding and
  • establishing social networks.