Periodontal diseases are a group of oral inflammatory diseases caused by bacterial plaque and influenced by host response factors
. There are two main types of conditions; gingivitis which is inflammation of soft tissues surrounding the tooth (the gingiva), and periodontitis involving apical migration of the periodontal ligament attachment and destruction of the connective tissue and alveolar bone that support the teeth
Some of the important clinical features include alterations in the gingival color, pocket depth, position of the epithelial attachment and tendency to bleeding
. In most developed countries, pregnancies are planned, complications are few and outcomes are generally favorable for both mother and infant, however, adverse outcomes are far more frequent in the developing world
. Much of the published research in the area of adverse pregnancy outcomes, are based on proxy outcomes for mortality and severe morbidity. The most commonly studied of these proxies being low birth weight (LBW) and its constituents, preterm birth and intrauterine growth retardation (IUGR)
Namiro et al. also found that preterm birth (PTB) and low birth weight (LBW) are more prevalent in developing than developed countries
. South Asia and Sub-Saharan Africa account for almost two-thirds of the world’s preterm babies
. In a previous survey in Uganda, one in seven newborn babies had LBW and required extra care to survive and thrive
. Low birth weight, i.e. birth weight of <2.5 kg, remains a significant public health problem in many parts of the world and is associated with a range of both short- and long-term adverse effects
. Systemic maternal infections are hypothesized to raise the risk of placental infection, premature rupture of membranes, premature labor and preterm birth by release of inflammatory cytokines and increased prostaglandin production
. Periodontal disease as a low grade chronic infection for example can be a challenge at systemic level due to the large epithelial surface that could be ulcerated in the periodontal pockets
Although a number of studies have shown that bacterial vaginosis is related to preterm birth and low birth weight, which in effect is a significant cause of morbidity and mortality, it is also possible that other infectious processes including periodontal disease contribute to PT/LWB
Indeed recent years have witnessed an increase in research evidence suggesting associations between periodontal disease and an increase in systemic disease
. After the publication of results by Offenbacher and co-authors in 1996
 from a case controlled study suggesting that women who delivered PT/LBW infants had poorer periodontal health than mothers with normal birth weight, a number of studies have come up trying to validate this observation
. The majority of the studies, especially those carried out in economically disadvantaged populations; suggest that periodontal disease is associated with increased risk of various adverse pregnancy outcomes such as preterm birth and low birth weight
Clinical trials at the Center for Oral and Systemic Disease at the University of North Carolina, reported the presence of higher levels of Porphyromonas gingivalis, Bacteroides forsythus, Actinobacillus actinomycetemcomitans and Treponema denticola, organisms normally associated with periodontal disease, in mothers of PTB and LBW babies as compared to normal controls
Opinion seemed to defer early when investigators like McGaw (2002) suggested that prospective and eventually interventional studies are necessary before periodontitis can be considered as a causal factor for PLBW
. In a meta-analysis, Khader et al., suggested that appropriate evidence was not available from good-quality observational research that could support the association between periodontal disease and PTB/PLBW
Some intervention studies suggest a reduction in the risks of preterm birth and preterm low birth weight after mechanical periodontal therapy during pregnancy. López et al. found a reduction in the rate of preterm births and/or low birth weight in women that received periodontal treatment before the 28th gestation week when they were compared with women that did not receive any treatment. This reduction was significant for periodontally healthy women compared with women with gingivitis
, and with periodontitis
In a systematic review by Scannapieco et al.
, where they selected 12 cases that they thought were high quality research out of the identified 660 studies, their conclusion was suggestive of periodontal disease being a risk factor for PT and LBW although they were cautious and recommended further longitudinal, epidemiological and interventional studies.
Another systematic review published in 2005 by Xiong et al. analyzed the results of 25 articles. The majority, 18 out of the 25 studies, suggested an association between periodontal disease and increased risk of adverse pregnancy outcomes
. Paquette (2006), however, noted that in spite of the building evidence supporting an association between periodontal disease and adverse pregnancy outcomes; there remains some potential bias due to inconsistencies in the definition of periodontal disease and the relatively limited number of randomized controlled trial studies
On the other hand, some clinical and laboratory studies have shown that intrauterine infections are highly prevalent among women who give birth prematurely
. Although the ascending infection from the vagina is considered the most common route of infection, they also suggest a hematogenous spread of organisms from other body sites to the uterus as a second route. Indeed organisms with an oral origin, such as Fusobacterium nucleatum and Capnocytophaga spp have been associated with intrauterine infections; F. nucleatum being one of the most frequently isolated microorganism from the infected uterus
In periodontal disease, transient bacteremia may occur probably leading to selective colonization of undesired sites
. Studies by Han et al. have shown that hematogenous injection of orally related F. nucleatum resulted in preferential localization to placental blood vessels from which it crossed the endothelium to the amniotic fluid and induced premature delivery, and stillbirths in a pattern similar to that observed in humans. This finding supports the hypothesis that after transient bacteremia, oral F. nucleatum translocates to the pregnant uterus and possibly to the fetus hematogenously
. Observations by Jiang et al.
 showed that several large clinical randomized controlled trials failed to demonstrate that periodontal therapy during pregnancy reduces the incidence of adverse pregnancy and birth outcomes. They proposed a new approach of using pre-conception treatment of periodontal disease to improve periodontal status during late pregnancy and subsequent birth outcomes: this may throw more light on the debate.
Uganda has a big economically disadvantaged population and, periodontal diseases have been documented as a public health problem especially in the rural communities with a prevalence of 62% in adults
. Coincidentally, there is also a high neonatal mortality in Uganda usually associated with preterm birth and low birth weight
. However, the contribution of periodontal diseases to these pregnancy outcomes is still unknown. The aim of the study was to determine the magnitude of periodontal diseases and their association to preterm births and low birth weight in postpartum mothers in Mbarara and Mulago referral hospitals.