Understanding Bacterial Vaginosis

Bacterial Vaginosis

Understanding Bacterial Vaginosis

Discover the bacteria responsible for bacterial vaginosis (BV), its effects on women and men, and its implications for fertility, miscarriage, and pregnancy. Learn about symptoms, treatments, and preventive measures to safeguard reproductive health.


Bacterial vaginosis (BV) is a common vaginal infection resulting from an imbalance in the vaginal microbiota. This condition predominantly affects women but can also impact men, particularly in the context of fertility and sexual health. Understanding the bacteria that cause BV and their implications for reproductive health is crucial. This comprehensive article explores the causes, symptoms, and treatments of BV in both women and men, and delves into its implications for fertility, miscarriage, and pregnancy.

Understanding Bacterial Vaginosis

What is Bacterial Vaginosis?
Bacterial vaginosis is an infection characterized by a disruption in the normal bacterial flora of the vagina. Normally, “good” bacteria (lactobacilli) outnumber “bad” bacteria (anaerobes). When anaerobes grow excessively, it disrupts this balance, leading to BV.

Causes of Bacterial Vaginosis
The exact cause of BV is not fully understood. However, several factors can increase the risk, including multiple sexual partners, douching, and a new sexual partner.

Common symptoms of BV include

  • Thin, grey, white, or green vaginal discharge
  • Foul-smelling “fishy” odour
  • Vaginal itching
  • Burning during urination


Diagnosis of Bacterial Vaginosis

Diagnosis typically involves a pelvic examination, assessment of symptoms, and laboratory tests of vaginal fluid to check for the balance of bacteria.

  • Key Bacteria Involved in BV
    Gardnerella vaginalis
    Gardnerella vaginalis is often the primary bacteria associated with BV. It can adhere to vaginal epithelial cells and form biofilms, making it difficult to eradicate.
  • Atopobium vaginae
    Atopobium vaginae is another anaerobic bacterium frequently found in women with BV. It often coexists with Gardnerella vaginalis and contributes to the formation of biofilms.
  • Prevotella Species
    Prevotella species are gram-negative anaerobes that increase in number during BV. They produce enzymes that break down vaginal mucins, leading to the characteristic discharge and odor.
  • Mobiluncus Species
    Mobiluncus species are curved, gram-negative anaerobes also linked to BV. They are typically found in conjunction with Gardnerella vaginalis and other anaerobes.
  • Mycoplasma hominis
    Mycoplasma hominis is a small bacterium without a cell wall, making it resistant to many antibiotics. It is commonly associated with BV and can exacerbate symptoms.
  • Other Anaerobes
    Other anaerobic bacteria, including Bacteroides and Peptostreptococcus, are also found in BV. These bacteria contribute to the complex microbial community that characterizes the infection.


The Role of Biofilms in BV

Biofilm Formation
Biofilms are structured communities of bacteria embedded in a self-produced matrix. In BV, biofilms protect bacteria from the immune system and antibiotics, making treatment more challenging.
Implications for Treatment
The presence of biofilms in BV necessitates targeted treatments that can penetrate these structures. Antibiotics like metronidazole and clindamycin are often used, but recurrent infections are common due to biofilm resilience.


Bacterial Vaginosis in Women

Prevalence and Risk Factors
BV is the most common vaginal infection among women aged 15-44. Risk factors include sexual activity, lack of vaginal lactobacilli, and hormonal changes.

Treatment Options for Women
Treatment usually involves antibiotics such as metronidazole or clindamycin. Both oral and topical forms are effective. It’s important to complete the full course of antibiotics to prevent recurrence.

Preventive Measures
Preventing BV involves avoiding douching, maintaining a balanced diet, using protection during sex, and limiting the number of sexual partners.

Impact on Fertility
BV can affect fertility by causing inflammation of the reproductive tract, which can hinder sperm mobility and embryo implantation. It can also lead to pelvic inflammatory disease (PID), which can cause infertility.

Implications for Miscarriage
Studies suggest that BV increases the risk of miscarriage, particularly in the second trimester. The infection can cause inflammation and disrupt the environment necessary for maintaining a pregnancy.

Effects on Pregnancy and Delivery
BV during pregnancy can lead to preterm labor, low birth weight, and postpartum endometritis. Pregnant women with BV are often treated with antibiotics to reduce these risks.


Bacterial Vaginosis in Men

Transmission to Men
While BV is not a traditional sexually transmitted infection, men can harbor the bacteria on their genitalia, potentially reinfecting female partners.

Symptoms in Men
Men typically do not show symptoms of BV but can experience urethritis or balanitis if the bacteria disrupt their natural microbial balance.

Treatment for Men
Treating male partners with antibiotics can help prevent the recurrence of BV in women, although this is not a standard practice.

Preventive Measures for Men
Men can reduce the risk of harbouring bacteria that cause BV by practicing good hygiene and using condoms during intercourse.

Impact on Male Fertility
The presence of BV-related bacteria in semen can negatively affect sperm quality and mobility, potentially impacting male fertility.


Bacterial Vaginosis and Sexual Health

Impact on Sexual Relationships
BV can cause discomfort and embarrassment, affecting intimacy and sexual relationships. Open communication and treatment can help manage these challenges.

Communication and Support
Couples should discuss BV openly and seek medical advice together to manage the condition effectively and support each other.

Implications for Fertility
How BV Affects Female Fertility

BV can lead to conditions like PID, which can cause scarring of the fallopian tubes and infertility. Inflammation caused by BV can also hinder sperm mobility and embryo implantation.

How BV Affects Male Fertility
Bacteria associated with BV can be present in semen, potentially affecting sperm quality and leading to fertility issues.

Bacterial Vaginosis and Miscarriage
Studies Linking BV to Miscarriage

Research indicates a higher risk of miscarriage among women with BV. The infection can cause inflammation and disrupt the uterine environment, crucial for maintaining a pregnancy.

Preventive Measures to Reduce Risk
Early diagnosis and treatment of BV in pregnant women can help reduce the risk of miscarriage. Regular prenatal check-ups are essential.


Bacterial Vaginosis During Pregnancy

Risks for Pregnant Women
BV increases the risk of preterm birth, low birth weight, and postpartum infections. Pregnant women with BV should be closely monitored and treated.

Managing BV in Pregnancy
Antibiotic treatment is recommended for pregnant women with BV to reduce the risk of complications. However, some antibiotics may not be safe in early pregnancy, so medical guidance is crucial.


Treatment Options for Bacterial Vaginosis

Antibiotic Treatments
Metronidazole and clindamycin are the primary antibiotics used to treat BV. Both oral and topical forms are available.

Natural Remedies and Alternative Treatments
Probiotics, garlic, and tea tree oil are often suggested as alternative treatments, but their efficacy is not well-established. Consult a healthcare provider before trying these remedies.

Recurrence Prevention
Completing the full course of antibiotics, avoiding douching, and maintaining good vaginal hygiene can help prevent recurrence.


Frequently Asked Questions

What is bacterial vaginosis?

Bacterial vaginosis is an infection caused by an imbalance of naturally occurring vaginal bacteria, leading to symptoms like discharge and odour.

Can men get bacterial vaginosis?
While men cannot get BV, they can harbour the bacteria on their genitals and potentially reinfect female partners.

How does BV affect fertility?
BV can cause inflammation and conditions like PID, which can hinder fertility in both women and men.

Is BV a sexually transmitted infection?
BV is not classified as a traditional STI, but sexual activity can increase the risk of developing it.

How is BV treated during pregnancy?
Pregnant women with BV are treated with antibiotics safe for use during pregnancy to prevent complications.

Can BV cause miscarriage?
Studies suggest that BV increases the risk of miscarriage, particularly in the second trimester, due to the inflammation it causes.



Bacterial vaginosis is a significant health concern for both women and men, with implications for fertility, miscarriage, and pregnancy. Understanding the bacteria that cause BV and the challenges posed by biofilms is crucial for effective diagnosis, treatment, and prevention. Early intervention and adherence to treatment are key to restoring and maintaining a healthy vaginal environment and mitigating the adverse effects of BV on reproductive health.

Click link to learn more about screening for BV based on a urine sample anywhere in the UK and Northern Ireland and about BV swabs in pregnancy.

Bacterial Vaginosis Urine Test

Vaginal Swab

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Bryan Beattie
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