Probiotic Therapy for the Reversal of Bacterial Vaginosis in Pregnancy

Preterm birth continues to provide the greatest challenge in perinatal health care in the developed world. It is a syndrome involving multiple causes and arises from a number of social, psychological, and biological determinants. It has been estimated that intrauterine infection accounts for at least 25-40% of spontaneous preterm births, with infection being the primary cause of extreme prematurity. Because infection-mediated preterm delivery mainly occurs in younger gestational ages (less than 28 weeks), these extremely premature babies not only have the risks associated with being born early, but are also likely to have severe morbidities associated with infection. Bacterial vaginosis (BV) is defined as a loss or significant depletion of lactobacilli coupled with an overgrowth of pathogenic bacteria and an increase in vaginal pH (>4.5). BV is common and occurs in 20% of the general female population, often without symptoms and is associated with a 40% increased risk of preterm birth. The clinical finding that lactobacilli is the dominant microbe in the vagina of women with a healthy pregnancy and full term delivery, supports the association of this species with a healthy pregnancy. BV is associated with an elevation of cervico-vaginal pro-inflammatory cytokines including IL-1β and IL-8 that are also associated with preterm labour; initiating the inflammatory cascade of events involved in labour may be the mechanism by which BV triggers preterm birth. However, not all women with BV will deliver preterm suggesting that variations in genetic susceptibility may underlie the host response to the presence of BV and the risk for preterm birth. Antibiotic therapy is the current treatment for BV, but the extent to which antibiotics can prevent preterm birth in women with BV remains somewhat uncertain, with conflicting results published in the literature. The apparent ineffective nature of antibiotic therapy, perhaps due to a lack of regrowth of lactobacilli following treatment, and the possibility that the pathogens have already induced inflammatory processes that will eventually induce preterm birth, emphasizes the need to continue to investigate the role of microbes during pregnancy. Probiotics have been suggested as an alternative to antibiotic therapy in restoring vaginal lactobacilli and reversing BV. The study seeks to determine whether Lactobacillus rhamnosus, GR-1 and Lactobacillus reuteri, RC-14 when administered to pregnant women diagnosed with bacterial vaginosis or intermediate flora will reverse the condition leading to a decrease in the inflammatory mediators involved in the cascade of infection/inflammation-mediated preterm birth.