From the Guidelines
Bacterial vaginosis (BV) can potentially contribute to preterm contractions and preterm birth, and treating the infection is important to reduce risks during pregnancy. BV is a vaginal infection characterized by an imbalance of normal vaginal bacteria, with an overgrowth of certain bacteria like Gardnerella vaginalis. In pregnant women, BV has been associated with a 1.5 to 2-fold increased risk of preterm labor and birth, as noted in studies such as 1 and 1. The inflammation caused by BV can lead to the production of cytokines and prostaglandins that may trigger uterine contractions and cervical changes.
Key Points to Consider
- The connection between BV and preterm birth is thought to involve bacterial ascension from the vagina to the uterus, which can cause inflammation of the fetal membranes and trigger the release of substances that initiate contractions.
- Treatment typically involves antibiotics such as metronidazole or clindamycin, with the optimal treatment regimen for pregnant women with bacterial vaginosis being unclear, as stated in 1 and 1.
- For pregnant women with symptomatic BV or those with a history of preterm birth, screening and treatment are particularly important, as emphasized in 1 and 1.
- While not all women with BV will experience preterm contractions, treating the infection is crucial to minimize risks during pregnancy, a point highlighted in 1 and 1.
Recommendations for Practice
- Screening for BV in asymptomatic pregnant women should be based on individual risk factors, such as previous preterm delivery or other risk factors for preterm delivery.
- Treatment of symptomatic cases should be based on the clinical situation, with consideration of the potential benefits and harms of treatment.
- Further research is needed to evaluate the benefit of screening and treating asymptomatic bacterial vaginosis in women at highest risk for preterm delivery, as noted in 1 and 1.
From the Research
Bacterial Vaginosis and Preterm Labor Contractions
- Bacterial vaginosis (BV) has been associated with an increased risk of preterm labor and delivery, as well as other adverse pregnancy outcomes 2, 3, 4.
- Studies have shown that BV can lead to preterm premature rupture of membranes, chorioamnionitis, and low birth weight 2, 3, 4.
- The prevalence of BV in pregnant women has been found to be around 20.3%, and it is significantly associated with preterm labor, premature rupture of membranes, and other adverse pregnancy outcomes 4.
- However, the effectiveness of antibiotic treatment in preventing preterm delivery in pregnant women with BV is still unclear, with some studies showing mixed results 5.
- A systematic review and individual participant data meta-analysis found that treatment of BV during pregnancy with metronidazole or clindamycin did not reduce preterm delivery or prolong pregnancy in any subgroup or when started earlier in gestation 5.
Risk Factors and Complications
- BV has been found to be a significant risk factor for preterm labor, premature rupture of membranes, and other adverse pregnancy outcomes 2, 3, 4.
- The risk of preterm labor and delivery is higher in women with BV, especially those with a history of preterm delivery 4.
- BV has also been associated with an increased risk of sexually transmitted infections, pelvic inflammatory disease, and other reproductive health complications 2, 6.
Diagnosis and Treatment
- BV can be diagnosed using clinical and microscopic methods, as well as highly sensitive and specific point-of-care tests 2.
- The current treatment for BV is antibiotic therapy, such as metronidazole and clindamycin, although the effectiveness of these treatments in preventing preterm delivery is still unclear 6, 5.
- New approaches to treatment and prevention, including probiotics, vaginal microbiome transplantation, and pH modulation, are being explored 6.