007.Recent advances in understanding and preventing pre-term birth - the oral health connection

Pre-term birth remains one of the major unsolved problems in human health. The incidence is increasing in many Western countries, despite several decades of research studies aimed at findings ways that early birth may be prevented. Nearly two-thirds of very early pre-term births are associated with features of inflammation in the newborn, suggesting that infection may be the origin. Many studies have focussed on the possibility that pre-labour rupture of membranes or the early onset of uterine activity may result from infection spreading upward from the vagina. Unfortunately, trials designed to identify potential pathogens in the genital tract followed by appropriate use of antibiotics have failed to prevent prematurity. The strong association between features of intra-uterine inflammation and pre-term birth, and the ineffectiveness of antibiotics to prevent the problem, suggest that the source of inflammation may be from a distant site. We are addressing the possibility that the site may be the gums. Periodontal disease affects 15% of the adult Australian population, is often undiagnosed and is not responsive to systemic antibiotic therapy. In our pregnant population, we have shown that periodontal disease is strongly associated with low birth weight. Our sheep studies have taught us that the lipopolysaccharides (LPS) from periodontal pathogens, when injected into the amniotic cavity, have much greater lethality than enteric LPS, and similar effects in inducing inflammation. We are now investigating the effects of treating periodontal disease during mid-pregnancy in a randomised controlled trial, which aims to screen approximately 5000 pregnant women and allocates those with periodontal disease to treatment during pregnancy or soon after. This study is known as the Smile Study and commenced in February 2005. Improving oral health is an exciting, but yet unproven, strategy by which a major health problem may be prevented by a relatively simple and community-based intervention.