ABSTRACTBackground. Bacterial vaginosis is a clinical entity characterized by offensive vaginal discharge caused by a disturbance of the normal vaginal bacterial flora. The hydrogen peroxidase producing lactobacilli are replaced by several anaerob bacteriae and the vaginal pH is increased. Bacterial vaginosis during pregnancy is associated with preterm delivery and as much as 40% of preterm deliveries can be linked to bacterial vaginosis. Preterm delivery is the major cause of neonatal morbidity and mortality. The exact pathogenesis for bacterial vaginosis leading to obstetric complications has not been established, though ascending inflammation and initiation of immunological cascades have been proposed.The treatment for bacterial vaginosis is antimicrobial therapy, most commonly Metronidazole or Clindamycin, administered orally or intravaginally. Several studies undertaking the task of preventing obstetric complications by treating bacterial vaginosis with antibiotics have been inconclusive with respect to treatment recommendations. The current guidelines recommend treatment of symptomatic bacterial vaginosis in pregnancy, but not screening of asymptomatic women. Method. Litterature searches in Cochrane library, Pubmed and Embase were performed for the periode 1994 - September 2009 examining whether antibiotics were successful in preventing obstetric complications such as preterm delivery, late abortions and low birthweight. Results. Antibiotics are effective treatment of bacterial vaginosis. The findings were inconclusive in regards to the prevention of preterm birth, late miscarriage and low birthweight. Review articles have proven unable to draw firm conclusions in regards to the effect of interventions for prevention of preterm birth. However, several studies published in recent years with interventions performed early in pregnancy have shown promising results with respect to preterm birth. Discussion. One major methodological problem in reviewing litterature on bacterial vaginosis and pregnancy complication is the heterogeneity with respect to study design, diagnostic measures, onset of treatment, as well as treatment regime. Moreover, there seems to be a lack of understanding of the exact microbiological processes of bacterial vaginosis leading to obstetric complications. Recently published papers have undertaken the task of identifying the microbiological markers of bacterial vaginosis preceding complications. Conclusion Early intervention with antimicrobial treatment has shown promising results in treatment of bacterial vaginosis in order to prevent complications such as preterm birth. Before large screening programs can be implemented, the effect of early antimicrobial treatment on clinically significant endpoints needs to be documented in large-scale controlled studies with standardised diagnostic procedures and treatment regimes. Furthermore, identification of the exact microbiological processes needs to be identified.