The Prevention of Adverse Pregnancy Outcomes by Periodontal Treatment (PROBE) Intervention Study

Periodontitis is one of the most common and chronic inflammatory oral conditions reaching approximately 20 - 60 % of the global population. The disease is characterized as a set of inflammatory conditions affecting the tissues surrounding the teeth. In the early stages, called gingivitis, where the disease is still reversible, the gums can become swollen, red and may bleed. Later in the disease development, periodontitis will progress into a more chronic condition. If untreated, periodontitis can cause tooth loss resulting in several complications including impaired speech, low self-esteem and reduced ability to eat freely and accumulating evidence has now linked periodontitis to a wide range of common medical conditions.

Pregnant women are susceptible to develop periodontitis due to hormonal changes leading to increased blood flow, plaque retention and risk of gingival infection, that may progress to periodontitis if persisting untreated. The prevalence of periodontitis in pregnancy has not been systematically assessed and varies significantly across studies with a range of 0 % -61 %. This large variation might be attributed to the diverse definitions of periodontitis. Still, optimal oral health care during pregnancy is often neglected and numbers from the Danish Dental Association indicate that 40% of Danish women in childbearing age do not visit a dentist regularly. Apart from the oral consequences resulting from periodontitis the condition is accompanied by a low-grade systemic inflammation. The systemic inflammation caused by periodontitis during pregnancy may have consequences beyond the oral cavity. Systematic reviews have shown that women with periodontitis can adversely influence the future health and metabolism of the offspring by an increased risk of preterm birth (< 37 weeks gestation) and delivering babies with low-birth-weight (< 2.5 kg). However, the biological mechanism underlying the link between periodontitis and adverse pregnancy outcomes is not fully known.

Early prevention of periodontal disease among pregnant women may have beneficial effects for both the mother and child. Providing periodontal treatment for pregnant women might reduce the risk of preterm birth, low birthweight as well as risk markers for pre-eclampsia and gestational disease. The idea and ambition of the prevention of adverse pregnancy outcomes by periodontal treatment' (PROBE) controlled intervention study is to investigate the beneficial effect of treatment of periodontal disease during pregnancy on fetal growth, preterm delivery and birth weight. Firstly, by investigating the prevalence of periodontitis among pregnant women. Secondly to prevent development of periodontal disease and the related systemic inflammation during pregnancy by intervening with periodontal treatment to reduce the risk of pregnancy and birth related outcomes. Reducing the development of these outcomes are expected to limit the risk of later development of metabolic disturbances in the offspring. Another implication of minimizing the prevalence of periodontitis is the potential reduction in other chronic diseases that periodontitis has been linked to, e.g. diabetes, cardiovascular disease and Alzheimer's.

If the key findings from the PROBE study are positive, the main message will be that oral hygiene and prevention of periodontitis during pregnancy are important and that treatment and regular visits to a dentist needs priority during pregnancy. Offering free dental care during pregnancy in Denmark would in the already established clinics be an easy implementable strategy to reduce adverse pregnancy and birth related outcomes. There will be economic costs related to providing free dental care, but the long-term beneficial effects both for the women and children as well as for society are expected to be significant and may exceed the costs of the intervention.

The overall aims of the study are to: