Asymptomatic Lactobacillus in Pregnancy

Diagnosis and Treatment

Bacterial vaginosis (BV) involves an imbalance in the vaginal bacterial ecosystem characterized by a decrease in hydrogen peroxide-producing lactobacilli and an increase in Gardnerella vaginalis, anaerobes, and mycoplasmas, and is diagnosed using Amsel clinical criteria or Gram stain, as recommended by the American Academy of Family Physicians 1
The American College of Physicians recommends diagnosing BV using Amsel clinical criteria (3 of 4 criteria: vaginal pH >4.7, presence of clue cells, thin homogeneous discharge, and amine "fishy odor") or Gram stain 2
The Infectious Diseases Society of America guidelines recommend screening for and treating asymptomatic bacteriuria in pregnancy, but this refers to urinary tract bacteria, not vaginal Lactobacillus colonization, with a strength of evidence rated as strong 3, 5

Antimicrobial treatment of asymptomatic colonization may disrupt the normal vaginal microbiome without providing measurable improvement in morbidity or mortality, according to the Infectious Diseases Society of America 3
Treatment of asymptomatic colonization could lead to adverse effects from antibiotics and development of bacterial resistance, as reported in the Annals of Internal Medicine 5

For women with a history of preterm delivery, monitoring of the vaginal microbiome may be appropriate, but treatment should be reserved for diagnosed infections, not normal Lactobacillus colonization, as recommended by the American Academy of Family Physicians 1

The American College of Physicians recommends avoiding confusion between normal Lactobacillus colonization and bacterial vaginosis, which requires specific diagnostic criteria 2
The Infectious Diseases Society of America recommends avoiding prescription of antibiotics for normal vaginal flora, as this may disrupt the beneficial microbiome and lead to antibiotic resistance 3
The Annals of Internal Medicine recommends avoiding overlooking the importance of distinguishing between asymptomatic bacteriuria (in urine), which requires treatment in pregnancy, and normal vaginal Lactobacillus colonization, which does not 5