Bacterial vaginosis

Exam relevance: in 5 of 197 board exam reports · rank 101

Synonyms: BV, Gardnerella
Specialty: Gynaecology · Vulva & vagina
Images: Histology & cytology 4 · Diagram 1 · Endoscopy & gross 2
Exam relevance: 5 of 197 reports · rank 101
In the app: 2 flashcards · GynFuchs
Last updated: 10/2026 · Dr. Pascal Bafteh

Contents

Images (7)
Definition
Clinical features
Diagnosis
Keep learning in the app
Further reading (selection)
Cross-references

Images (7)

Bacterial vaginosis – Histology & cytology: Clue cells in phase contrast: granulated cytoplasm and roughened cell borders — Clue cells in phase contrast: granulated cytoplasm and roughened cell bordersImage: Dr Graham Beards (Wikimedia Commons) · CC BY-SA 4.0 · Source

Bacterial vaginosis – Diagram: Comparison chart: on the left, a squamous epithelial cell with rod-shaped normal flora; on the right, a cell densely covered with bacteria in bacterial vaginosis — Comparison chart: on the left, a squamous epithelial cell with rod-shaped normal flora; on the right, a cell densely covered with bacteria in bacterial vaginosisImage: Mikael Häggström, M.D. (Wikimedia Commons) · CC0 · Source

Bacterial vaginosis – Endoscopy & gross — Image: Dr Graham Beards (Wikimedia Commons) · CC BY-SA 4.0 · Source

Bacterial vaginosis – Histology & cytology: Lactobacilli (Döderlein's bacilli) in phase contrast — pure culture of Lactobacillus acidophilus with an inserted scale bar — Lactobacilli (Döderlein's bacilli) in phase contrast — pure culture of Lactobacillus acidophilus with an inserted scale barImage: Josef Reischig, CSc. (Wikimedia Commons) · CC BY-SA 3.0 · Source

Bacterial vaginosis – Histology & cytology — Image: Mikael Häggström , M.D. (Wikimedia Commons) · CC0 · Source

1 / 7

Definition

What Vaginosis Is

Basic process: displacement of lactobacilli by anaerobes.
Key organism: Gardnerella vaginalis, Atopobium, Prevotella.
Why it is not a true colpitis: few signs of inflammation, few leukocytes.
Typical complaint: thin, greyish-white discharge with fishy odour.

Clinical features

Why This Matters in Pregnancy

The risk: preterm birth, premature membrane rupture.
A history of preterm birth requires: vaginal environment assessment.

Diagnosis

Amsel's Criteria

For diagnosis, you need: three of four Amsel criteria.
First criterion: homogeneous, thin, greyish-white discharge.
Second criterion: a vaginal pH above 4.5.
Third criterion: positive amine test (whiff test) with KOH.
Fourth criterion: detection of clue cells in the wet mount.
The alternative microscopic system: Nugent score (Gram stain, 0–10 points).

PH and Amine Test

Physiological vaginal pH in women of reproductive age: pH 3.8–4.5 (acidic).
What produces the acidic pH: lactobacilli (glycogen → lactic acid).
A pH above 4.5 is found in: vaginosis, trichomoniasis, atrophy.
In candidiasis: pH value in normal range (3.8–4.5).
Amine test: 10% potassium hydroxide causes fishy odour.
Source of error in pH measurement: blood, semen, lubricants raise pH value.

Keep learning in the app

In the GynFuchs app you can learn Bacterial vaginosis with flashcards, exam questions and image tasks (colposcopy, ultrasound, CTG) – free, in your browser or as an app.

In the app: 2 flashcards on this topic

Open in browser About GynFuchs →