What is the recommended treatment for Gardnerella vaginalis infection in pregnancy?

Treatment of Gardnerella vaginalis (Bacterial Vaginosis) in Pregnancy

For Gardnerella vaginalis infection in pregnancy, clindamycin vaginal cream 2% is the preferred treatment during the first trimester, while metronidazole (oral or vaginal) can be used in the second and third trimesters. 1

Diagnosis of Bacterial Vaginosis

Before treatment, diagnosis should be confirmed using Amsel criteria (3 of 4 required):

• Homogeneous, white, thin discharge that smoothly coats the vaginal walls
• Presence of clue cells on microscopic examination
• Vaginal fluid pH >4.5
• Fishy odor of vaginal discharge before or after addition of 10% KOH (whiff test)

Treatment Recommendations by Trimester

First Trimester

• Preferred treatment: Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days 1
• Metronidazole is contraindicated during the first trimester due to potential concerns about teratogenicity 1

Second and Third Trimesters

• Recommended regimen: Metronidazole 250mg orally three times a day for 7 days 1
• Alternative regimens:
  • Metronidazole 500mg orally twice daily for 7 days 1
  • Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days 1
  • Clindamycin 300mg orally twice a day for 7 days 1

Special Considerations

Symptomatic vs. Asymptomatic Infection

• All symptomatic pregnant women should be treated regardless of trimester 1
• High-risk pregnant women (those with previous preterm delivery) with asymptomatic BV should be screened and treated to reduce the risk of preterm delivery 1, 2
• Treatment should be conducted at the earliest part of the second trimester for asymptomatic high-risk women 1

Efficacy and Follow-up

• Treatment of BV in high-risk pregnant women has been shown to reduce preterm delivery in several randomized controlled trials 1
• A follow-up evaluation one month after completion of treatment is recommended for pregnant women to ensure treatment success 1
• Research shows that short courses of metronidazole therapy can achieve long-term suppression of bacterial vaginosis flora in 87% of pregnant women 3

Important Precautions

• Clindamycin cream is oil-based and may weaken latex condoms and diaphragms 1
• Patients should avoid consuming alcohol during treatment with metronidazole and for 24 hours thereafter 1
• The use of clindamycin vaginal cream during pregnancy requires caution as some studies have shown an increase in preterm deliveries 1
• While there have been concerns about metronidazole's potential teratogenicity based on animal studies, meta-analyses have not demonstrated consistent teratogenic or mutagenic effects in humans 1

Treatment Outcomes

BV during pregnancy is associated with adverse pregnancy outcomes including:

• Premature rupture of membranes
• Preterm labor and delivery
• Postpartum endometritis
• Post-cesarean wound infections

Appropriate treatment can reduce these risks, particularly in women with a history of preterm delivery 1, 2.

The bacterial flora that characterizes BV has been recovered from the endometria and salpinges of women with PID, highlighting the importance of effective treatment 1.

By following these treatment guidelines, clinicians can effectively manage Gardnerella vaginalis infections in pregnant women while minimizing risks to both mother and fetus.