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Low birth weight, defined as birth weight less than 2,500 g, continues to be a significant public health issue in both developed and developing countries. This obstetric complication is usually a direct result of preterm labour, in which case it is referred to as preterm delivery of low-birthweight infants (PLBW). Introduction of neonatal intensive care methods during the 1960s and the subsequent development of surfactant therapy in the 1980s resulted in improvements in the survival rates of PLBW neonates. However, compared with infants of normal birth weight, PLBW infants are still 40 times more likely to die during the neonatal period.12 PLBW births represent approximately 10% of all live births in North America, and medical care for these infants is estimated to exceed $5 billion US annually.

For a long time we've known that risk factors such as smoking, alcohol use, and drug use contribute to mothers having babies that are born prematurely at a low birth weight.

Now evidence is mounting that suggests a new risk factor – periodontal disease. Pregnant women who have periodontal disease may be seven times more likely to have a baby that is born too early and too small.

More research is needed to confirm how periodontal disease may affect pregnancy outcomes. It appears that periodontal disease triggers increased levels of biological fluids that induce labor. Furthermore, data suggests that women whose periodontal condition worsens during pregnancy have an even higher risk of having a premature baby.

All infections are cause for concern among pregnant women because they pose a risk to the health of the baby. The Academy recommends that women considering pregnancy have a periodontal evaluation.

 

SCIENTIFIC PAPERS

Alves, R. T. and R. A. Ribeiro (2006). "Relationship between maternal periodontal disease and birth of preterm low weight babies." Pesqui Odontol Bras 20(4): 318-23.

ABSTRACT: It has been recently suggested that periodontal disease is an associated factor for prematurity and low birth weight. The aim of this work was to assess the periodontal status of puerperae and determine its possible relationship with preterm low birth weight (PLBW) delivery. The sample included 59 women seen at two maternity hospitals in Juiz de Fora, MG, Brazil. Nineteen mothers had premature and low birth weight babies (gestational age below 37 weeks and birth weight below 2,500 g--group I), and 40 had mature, normal weight babies (gestational age over 37 weeks and birth weight over 2,500 g--group II). The mothers' data were obtained from medical files, interview, and periodontal clinical examination carried out up to 48 hours after delivery. The Periodontal Screening and Recording (PSR) was used for periodontal assessment. The association between periodontal disease and PLBW was expressed as odds ratio (OR). There was a higher rate of periodontal disease in group I (84.21% - 16/19) as compared with group II (37.5% - 15/40). The data also showed a significant association between periodontal disease and PLBW (OR = 8.9 - 95% CI: 2.22-35.65--p = 0.001). It was concluded that maternal periodontal disease was an associated factor for prematurity and low birth weight in this sample.

Barnes, C. M. (2007). "Treatment of periodontal disease and the risk of preterm birth." Pract Proced Aesthet Dent 19(2): 118.

Dasanayake, A. P., S. Russell, et al. (2003). "Preterm low birth weight and periodontal disease among African Americans." Dent Clin North Am 47(1): 115-25, x-xi.

ABSTRACT: African Americans consistently experience higher rates of preterm and low birth weight (LBW) deliveries than do whites. LBW and preterm infants are more likely to die before their first birthday and survivors may suffer from a number of health problems. Therefore, identification of modifiable risk factors for preterm deliveries and LBW has considerable public health significance. Pregnant women's poor periodontal healtlh is emerging as one such factor. Maternal clinical periodontal status and bacteriologic and immunologic profiles related to periodontal disease have been associateted with risk of fetal growth and preterm LBW, and periodontal treatment during pregnancy has reduced the incidence of preterm deliveries. This article reviews the literature on the above association and presents data from a previously published prospective study of predominantly African Americans to show that preterm LBW deliveries are associated with higher midtrimester maternal serum antibody levels against Porphyromonas gingivalis.

Davenport, E. S., C. E. Williams, et al. (2002). "Maternal periodontal disease and preterm low birthweight: case-control study." J Dent Res 81(5): 313-8.

ABSTRACT: Periodontal disease has been suggested to be an important risk factor for preterm low birthweight (PLBW). Here we report a case-control study of 236 cases (infants < 37 wks and weighing < 2499 g) and a daily random sample of 507 controls (> or = 38 wks and weighing > or = 2500 g). Clinical periodontal indices were measured on the labor wards. Associated risk factors for periodontal disease and PLBW were ascertained by means of a structured questionnaire and maternity notes. The risk for PLBW decreased with increasing pocket depth (odds ratio [OR] 0.83, 95% confidence interval [CI] 0.68 to 1.00). After adjustment for maternal age, ethnicity, maternal education, smoking, alcohol consumption, infections, and hypertension during pregnancy, this decreased further (OR 0.78, 95% CI 0.64 to 0.99). We found no evidence for an association between PLBW and periodontal disease. Our results do not support a specific drive to improve periodontal health of pregnant women as a means of improving pregnancy outcomes.

Davenport, E. S., C. E. Williams, et al. (1998). "The East London Study of Maternal Chronic Periodontal Disease and Preterm Low Birth Weight Infants: study design and prevalence data." Ann Periodontol 3(1): 213-21.

ABSTRACT: The influence of subject-based and environmental factors on the balance between the subgingival microbial challenge and the host response in periodontal diseases illustrates the intimate link between oral and systemic health. From this stems the hypothesis that the persistent Gram-negative challenge and associated inflammatory sequelae in periodontal disease may have consequences extending beyond the periodontal tissues themselves. This paper addresses the design of a case-control study to examine the relationship between preterm low birth weight (PLBW) and maternal periodontal disease. We present preliminary data on the prevalence of these 2 conditions in a group of mothers at the Royal Hospitals Trust, London, U.K. Cases are defined as mothers delivering an infant weighing less than 2,500g before 37 weeks gestation and controls as mothers delivering an infant of more than 2,500g after 38 weeks. We estimated that a study involving 800 mothers (1:3 case:control) should have sufficient power to detect an association with a minimum odds ration of 3 at the 5% significance level. Demographic details of 177 subjects demonstrated that they were representative of the local population, and the prevalence of PLBW was within the expected range. However, the extent and severity of periodontal disease were higher than predicted and may have reflected elevations in gingival inflammation associated with pregnancy. The final outcome of the study should help determine the need for further interventionist studies to demonstrate a causal relationship between periodontal disease and PLBW, as well as provide information on the prevalence of periodontal diseases in this study population.

Garvin, J. (2006). "Periodontal treatment does not reduce the risk of preterm delivery, study finds." J Am Dent Assoc 137(12): 1642-3.

Gazolla, C. M., A. Ribeiro, et al. (2007). "Evaluation of the incidence of preterm low birth weight in patients undergoing periodontal therapy." J Periodontol 78(5): 842-8.

ABSTRACT: BACKGROUND: Preterm low birth weight was reported to be related to periodontal infections that might influence the fetus-placenta complex. The aim of this study was to provide periodontal treatment for pregnant women and to evaluate if this treatment can interfere with pregnancy duration and weight of the newborn. METHODS: The sample consisted of 450 pregnant women who were under prenatal care at a polyclinic in Tres Coracoes, Brazil. Women with risk factors, such as systemic alterations (ischemic cardiopathy, hypertension, tuberculosis, diabetes, cancer, anemia, seizure, psychopathology, urinary tract infection, sexually transmitted diseases, asthma, and human immunodeficiency virus), and/or users of alcohol, tobacco, and drugs were excluded from the study. Data related to age, socioeconomic level, race, marital status, number of previous pregnancies, and previous preterm delivery also were evaluated. Initially, the sample was divided into two groups: 122 healthy patients (group 1) and 328 patients with periodontal disease (group 2). In group 2, 266 patients underwent treatment and 62 patients dropped out. After mothers gave birth, pregnancy duration and the weight of all infants were analyzed and recorded. RESULTS: There was no statistical difference between the healthy and treated groups. However, there was a difference in the non-treated group, with a 79% incidence of preterm low birth weight. Educational level, previous preterm birth, and periodontal disease were related significantly to preterm delivery (P <0.001). CONCLUSION: Periodontal disease was related significantly to preterm low birth weight.

Goepfert, A. R., M. K. Jeffcoat, et al. (2004). "Periodontal disease and upper genital tract inflammation in early spontaneous preterm birth." Obstet Gynecol 104(4): 777-83.

ABSTRACT: OBJECTIVE: To estimate the relationship between maternal periodontal disease and both early spontaneous preterm birth and selected markers of upper genital tract inflammation. METHODS: In this case-control study, periodontal assessment was performed in 59 women who experienced an early spontaneous preterm birth at less than 32 weeks of gestation, in a control population of 36 women who experienced an early indicated preterm birth at less than 32 weeks of gestation, and in 44 women with an uncomplicated birth at term (>or = 37 weeks). Periodontal disease was defined by the degree of attachment loss. Cultures of the placenta and umbilical cord blood, cord interleukin-6 levels, and histopathologic examination of the placenta were performed for all women. RESULTS: Severe periodontal disease was more common in the spontaneous preterm birth group (49%) than in the indicated preterm (25%, P =.02) and term control groups (30%, P =.045). Multivariable analyses, controlling for possible confounders, supported the association between severe periodontal disease and spontaneous preterm birth (odds ratio 3.4, 95% confidence interval 1.5-7.7). Neither histologic chorioamnionitis, a positive placental culture, nor an elevated cord plasma interleukin-6 level was significantly associated with periodontal disease (80% power to detect a 50% difference in rate of histological chorioamnionitis, alpha = 0.05). CONCLUSION: Women with early spontaneous preterm birth were more likely to have severe periodontal disease than women with indicated preterm birth or term birth. Periodontal disease was not associated with selected markers of upper genital tract inflammation. LEVEL OF EVIDENCE: II-2

Goldenberg, R. L. and J. F. Culhane (2006). "Preterm birth and periodontal disease." N Engl J Med355(18): 1925-7.

Hefti, A. F. (2006). "Periodontal therapy and preterm birth." Int J Dent Hyg 4 Suppl 1: 39-42; discussion 50-2.

Holbrook, W. P., A. Oskarsdottir, et al. (2004). "No link between low-grade periodontal disease and preterm birth: a pilot study in a healthy Caucasian population." Acta Odontol Scand 62(3): 177-9.

Hubbard, S. and A. Shanks (2004). "Relationship between periodontal disease and preterm low birth weight infants." Tenn Med 97(2): 81.

Jarjoura, K., P. C. Devine, et al. (2005). "Markers of periodontal infection and preterm birth." Am J Obstet Gynecol 192(2): 513-9.

ABSTRACT: OBJECTIVE: This study was undertaken to explore the relationship between clinical, microbiologic, and serologic markers of periodontitis and preterm birth (PTB). STUDY DESIGN: We compared women with a singleton gestation giving birth before the 37th week (cases, n = 83) with term delivery controls (n = 120). Periodontal examination and collection of dental plaque and blood samples were performed within 48 hours after delivery. Microbial levels and maternal immunoglobulin G titers to oral bacteria were analyzed. Multivariate regression models were fitted controlling for common covariates. RESULTS: Cases showed greater mean attachment loss (1.7 vs 1.5 mm, P = .003) and higher prevalence of periodontitis (30.1% vs 17.5%, P = .027). No differences in microbial or serum antibody levels were detected between the groups. Logistic regression revealed that PTB was associated with attachment loss (adjusted odds ratio: 2.75, 95% CI: 1.01-7.54). Linear regression indicated a significant ( P = .04) association between attachment loss and low birth weight (LBW). CONCLUSION: The data support the notion that periodontitis is independently associated with PTB and LBW.

Jeffcoat, M. K. (2000). "Preterm birth, osteoporosis, and periodontal disease." Compend Contin Educ Dent Suppl(30): 5-11; quiz 65.

ABSTRACT: The purpose of this two-part article is to review two major events in the life span of a woman. These include the putative relationship between oral health, pregnancy, and postmenopausal osteoporosis. Current knowledge about risk factors for preterm birth and for osteoporosis are discussed. The newest studies that address the relationship between oral and systemic health are also reviewed.

Jeffcoat, M. K., N. C. Geurs, et al. (2001). "Periodontal infection and preterm birth: results of a prospective study." J Am Dent Assoc 132(7): 875-80.

ABSTRACT: BACKGROUND: Previous studies have suggested that chronic periodontal infection may be associated with preterm births. The authors conducted a prospective study to test for this association. METHODS: A total of 1,313 pregnant women were recruited from the Perinatal Emphasis Research Center at the University of Alabama at Birmingham. Complete periodontal, medical and behavioral assessments were made between 21 and 24 weeks gestation. After delivery, medical records were consulted to determine each infant's gestational age at birth. From these data, the authors calculated relationships between periodontal disease and preterm birth, while adjusting for smoking, parity (the state or fact of having born offspring), race and maternal age. Results were expressed as odds ratios and 95 percent confidence intervals, or CIs. RESULTS: Patients with severe or generalized periodontal disease had adjusted odds ratios (95 percent CI) of 4.45 (2.16-9.18) for preterm delivery (that is, before 37 weeks gestational age). The adjusted odds ratio increased with increasing prematurity to 5.28 (2.05-13.60) before 35 weeks' gestational age and to 7.07 (1.70-27.4) before 32 weeks' gestational age. CONCLUSIONS: The authors' data show an association between the presence of periodontitis at 21 to 24 weeks' gestation and subsequent preterm birth. Further studies are needed to determine whether periodontitis is the cause. CLINICAL IMPLICATIONS: While this large prospective study has shown a significant association between preterm birth and periodontitis at 21 to 24 weeks' gestation, neither it nor other studies to date were designed to determine whether treatment of periodontitis will reduce the risk of preterm birth. Pending an answer to this important question, it remains appropriate to advise expectant mothers about the importance of good oral health.

Jeffcoat, M. K., N. C. Geurs, et al. (2001). "Current evidence regarding periodontal disease as a risk factor in preterm birth." Ann Periodontol 6(1): 183-8.

ABSTRACT: Preterm birth, resulting in babies born too little and too soon, is a major cause of morbidity. Evidence indicates that infections can be major risk factors in preterm birth. Case-control studies point to an association between periodontal infection and increased rates of preterm birth. This paper summarizes evidence to date and the strategies that ongoing intervention studies are using to answer the fundamental clinical question: can periodontal therapy reduce the risk of preterm birth?

Jeffcoat, M. K., J. C. Hauth, et al. (2003). "Periodontal disease and preterm birth: results of a pilot intervention study." J Periodontol 74(8): 1214-8.

ABSTRACT: BACKGROUND: Previous case-control and prospective studies have shown an association between the presence of periodontitis and the risk of preterm birth (PTB). The goal of this pilot trial was to determine the feasibility of conducting a trial to determine whether treatment of periodontitis reduces the risk of spontaneous preterm birth (SPTB). METHODS: Three hundred sixty-six (366) women with periodontitis between 21 and 25 weeks' gestation were recruited and randomized to one of three treatment groups with stratification on the following two factors: 1) previous SPTB at <35 weeks and 2) body mass index <19.8 or bacterial vaginosis as assessed by Gram stain. The treatment groups consisted of: 1) dental prophylaxis plus placebo capsule; 2) scaling and root planing (SRP) plus placebo capsule; and 3) SRP plus metronidazole capsule (250 mg t.i.d. for one week). An additional group of 723 pregnant women meeting the same criteria for periodontitis and enrolled in a prospective study served as an untreated reference group. RESULTS: The rate of PTB at <35 weeks was 4.9% in the prophylaxis group, compared to 3.3% in the SRP plus metronidazole group and 0.8% in the SRP plus placebo group (P = 0.75 and 0.12, respectively). The rate of PTB at <35 weeks was 6.3% in the reference group. CONCLUSIONS: This trial indicates that performing SRP in pregnant women with periodontitis may reduce PTB in this population. Adjunctive metronidazole therapy did not improve pregnancy outcome. Larger trials will be needed to achieve statistical significance, especially at less than 35 weeks gestational age.

Khader, Y. S. and Q. Ta'ani (2005). "Periodontal diseases and the risk of preterm birth and low birth weight: a meta-analysis." J Periodontol 76(2): 161-5.

ABSTRACT: BACKGROUND: This meta-analysis of periodontal disease in relation to the risk of preterm birth/low birth weight (PTB/ LBW) is based on two case-control studies and three prospective cohort studies that met pre-stated inclusion criteria. METHODS: Information on the designs of the studies, characteristics of the study population, exposure and outcome measures, control for confounders, and risk estimates were abstracted independently by two investigators using a standard protocol. RESULTS: Pregnant women with periodontal disease had an overall adjusted risk of preterm birth that was 4.28 (95% confidence interval [CI], 2.62 to 6.99; P <0.005) times that risk for healthy subjects. The overall adjusted odds ratio of preterm low birth weight was 5.28 (95% CI, 2.21 to 12.62; P <0.005), while the overall adjusted odds ratio of a delivery of either PTB or LBW was 2.30 (95% CI, 1.21 to 4.38; P <0.005). CONCLUSIONS: Our findings indicate that periodontal diseases in the pregnant mother significantly increase the risk of subsequent preterm birth or low birth weight. While it remains important to promote good oral hygiene during routine prenatal visits, there is no convincing evidence, on the basis of existing case control and prospective studies, that treatment of periodontal disease will reduce the risk of preterm birth. Consequently, large randomized, placebo-controlled, masked clinical trials are required.

Konopka, T., M. Rutkowska, et al. (2003). "The secretion of prostaglandin E2 and interleukin 1-beta in women with periodontal diseases and preterm low-birth-weight." Bull Group Int Rech Sci Stomatol Odontol 45(1): 18-28.

ABSTRACT: Prematurity is of one of the main causes of neonatal morbidity and mortality. Clinical observations show, that periodontitis in pregnant women can be a direct risk factor for preterm labor, with a greater influence rate compared to other risk factors. The aim of the study was to asses the relationship between periodontal diseases and PLBW in the population of women from the Lower Silesian Region (Poland), and the evaluation of prostaglandin E2 (PGE2), interleukin-1 beta (IL-1 beta) levels in gingival cervicular (GCF) and blood serum in women with PLBW and women giving birth on time as well as secretion of these proinflammatory mediators in whole blood after bacterial lipopolysaccharide stimulation. The study group consisted of 84 women with PLBW (39.2% primiparous), aged 17-41 (mean 27.57). The controls were 44 women (47.7% primiparous) aged 16-38 (mean 26.36) who gave birth on time to a normal birthweight baby. PGE2 and IL-1 beta concentrations in serum and GCF were determined by means of immunoenzymatic method (EIA). In the studied population women over 28 years and exposed to medical risk factors had more frequent PLBW occurrence probability. In primiparous over 28 there is 4 times greater probability of preterm labor, and in case of the severe and generalized periodontitis presence there is 3.9 times higher possibility of PLBW compared to women with healthy periodontium. In all women with PLBW there is a significantly higher PGE2 and IL-1 beta concentration in GCF, and in primiparous also PGE2 level in blood serum, compared to controls.

Li, X. J., Y. Q. Sha, et al. (2004). "[Advances research of periodontal disease and preterm low birth weight deliveries]." Zhonghua Kou Qiang Yi Xue Za Zhi 39(4): 341-3.

Lin, D., K. Moss, et al. (2007). "Persistently high levels of periodontal pathogens associated with preterm pregnancy outcome." J Periodontol 78(5): 833-41.

ABSTRACT: BACKGROUND: Few studies examining the association between periodontal diseases and preterm birth have explored the underlying microbial and antibody responses associated with oral infection. METHODS: A nested case-control study was performed using data from a recent interventional trial following the delayed-treatment control group of 31 subjects with periodontal diseases. The levels of eight oral bacteria and the maternal immunoglobulin G (IgG) responses in serum to these bacteria were measured at antepartum and postpartum visits to determine the relationship to cases (preterm delivery <37 weeks' gestation) and controls (term delivery). RESULTS: Antepartum, the levels of periodontal pathogens tended to be higher in the preterm (case group) deliveries compared to the term deliveries (control group). Maternal anti-Porphyromonas gingivalis IgG was significantly lower in the preterm group compared to the term group (P = 0.028). Postpartum, levels of P. gingivalis, Tannerella forsythia, Prevotella intermedia, and Prevotella nigrescens were statistically significantly higher in preterm births compared to term deliveries, adjusting for baseline levels. The joint effects of red and orange microbial clusters were significantly higher in the preterm group compared to the term group. CONCLUSIONS: High levels of periodontal pathogens and low maternal IgG antibody response to periodontal bacteria during pregnancy are associated with an increased risk for preterm delivery. Further studies elucidating the role of the microbial load and maternal immune response as related to pregnancy outcome seem merited.

Lopez, N. J., I. Da Silva, et al. (2005). "Periodontal therapy reduces the rate of preterm low birth weight in women with pregnancy-associated gingivitis." J Periodontol 76(11 Suppl): 2144-53.

ABSTRACT: BACKGROUND: One hypothesis to explain the association between periodontal disease (PD) preterm/low birth weight (PT/LBW) is that PT/LBW may be indirectly mediated through translocation of bacteria or bacterial products in the systemic circulation. Transient bacteremias occur in subjects with marginal periodontitis or with gingivitis, and it is possible that bacteria and their products may reach the placental membranes hematogenously and provide the inflammatory effect to induce preterm labor. The effect of gingivitis as a potential risk factor for PT/LBW has still not been studied. A randomized controlled trial was undertaken to determine the effect of routine plaque control and scaling on the pregnancy outcomes in women with gingivitis. METHODS: Eight hundred seventy (870) pregnant women with gingivitis, aged 18 to 42, were enrolled while receiving prenatal care in Santiago, Chile. Women were randomly assigned in a two-to-one fashion to either a treatment group (N = 580), receiving periodontal treatment before 28 weeks of gestation or to a control group (N = 290), receiving periodontal treatment after delivery. Periodontal therapy consisted of plaque control, scaling, and daily rinsing with 0.12% clorhexidine. Maintenance therapy was provided every 2 to 3 weeks until delivery, and consisted of oral hygiene instruction and supragingival plaque removal by instrumentation, as needed. The primary outcomes assessed were delivery at less than 37 weeks of gestation or an infant weighing less than 2,500 g. RESULTS: Of the 870 women enrolled, 36 women (27 in the treatment group and nine in the control group) were excluded from the analyses for different reasons. The incidence of PT/LBW in the treatment group was 2.14% (12/560) and in the control group, 6.71% (19/283) (odds ratio [OR] 3.26; 95% confidence interval [CI] 1.56 to 6.83; P = 0.0009). Multivariate logistic regression analysis showed that, after adjusting for several known risk factors for PT/LBW, women with gingivitis were at a higher risk of PT/LBW than women who received periodontal treatment (OR 2.76; 95%CI 1.29 to 5.88; P = 0.008). CONCLUSIONS: Periodontal treatment significantly reduced the PT/LBW rate in this population of women with pregnancy-associated gingivitis. Within the limitations of this study, we conclude that gingivitis appears to be an independent risk factor for PT/LBW for this population.

Lopez, N. J., P. C. Smith, et al. (2002). "Higher risk of preterm birth and low birth weight in women with periodontal disease." J Dent Res 81(1): 58-63.

ABSTRACT: Pregnant women with periodontal disease (PD) may be at increased risk for having preterm low-birth-weight (PLBW) children. We investigated whether the maintenance of the mothers' periodontal health after 28 weeks' gestation reduces the risk of PLBW. Of the 639 women studied, 406 had gingivitis and received treatment before 28 weeks' gestation, and 233 had PD and were treated after delivery. Data about previous and current pregnancies and known risk factors were obtained from patients' medical records. Primary outcomes were delivery before 37 weeks' gestation or an infant with birth weight below 2500 g. The incidence of PLBW was 2.5% in periodontally healthy women, and 8.6% in women with PD (p = 0.0004, relative risk = 3.5, 95% CI, 1.7 to 7.3). Risk factors significantly associated with PLBW were previous PLBW, PD, fewer than 6 pre-natal visits, and low maternal weight gain. PD was associated with both preterm birth and low birth weight, independent of other risk factors.

Lopez, N. J., P. C. Smith, et al. (2002). "Periodontal therapy may reduce the risk of preterm low birth weight in women with periodontal disease: a randomized controlled trial." J Periodontol 73(8): 911-24.

ABSTRACT: BACKGROUND: Recent studies have suggested that periodontal disease is a risk factor for preterm low birth weight (PLBW). A randomized controlled trial was undertaken to help further evaluate the proposed association between periodontal disease and PLBW. METHODS: Four hundred pregnant women with periodontal disease, aged 18 to 35, were enrolled while receiving prenatal care in Santiago, Chile. Women were randomly assigned to either an experimental group (n = 200), which received periodontal treatment before 28 weeks of gestation or to a control group (n = 200) which received periodontal treatment after delivery. Previous and current pregnancies and known risk factors were obtained from patient medical records and interviews. The primary outcome assessed was the delivery at less than 37 weeks of gestation or an infant weighing less than 2,500 g. RESULTS: Of the 400 women enrolled, 49 were excluded from the analyses for different reasons. The incidence of PLBW in the treatment group was 1.84% (3/163) and in the control group was 10.11% (19/188), (odds ratio [OR] 5.49, 95% confidence interval [CI] 1.65 to 18.22, P= 0.001). Multivariate logistic regression analysis showed that periodontal disease was the strongest factor related to PLBW (OR 4.70, 95% CI 1.29 to 17.13). Other factors significantly associated with such deliveries were: previous PLBW (OR 3.98, 95% CI 1.11 to 14.21), less than 6 prenatal visits (OR 3.70, 95% Cl 1.46 to 9.38), and maternal low weight gain (OR 3.42, 95% CI 1.16 to 10.03). Conclusions: Periodontal disease appears to be an independent risk factor for PLBW. Periodontal therapy significantly reduces the rates of PLBW in this population of women with periodontal disease.

Lopez, R. (2005). "Periodontal disease, preterm birth and low birthweight." Evid Based Dent 6(4): 90-1.

Lopez, R. (2007). "Periodontal treatment in pregnant women improves periodontal disease but does not alter rates of preterm birth." Evid Based Dent 8(2): 38.

ABSTRACT: DesignThis was a multicentre randomised controlled trial (RCT).InterventionPregnant women were divided into two groups. Those to whom dental treatment was given had up to four visits of periodontal scaling and root planing using ultrasonic and hand instruments, with local anaesthesia as needed. Treatment recipients were also given instruction in oral hygiene and monthly tooth polishing and re-instruction in oral hygiene, with scaling and planing as needed. Control patients received only a brief oral examination at monthly follow-ups but attended the same number of visits as the treatment group. Patients in the control group were offered the same periodontal therapy after delivery.Outcome measureThe primary outcome was gestational age at delivery. Secondary outcomes included birth weight, the proportion of infants who were small for gestational age, Apgar scores, and admissions to a neonatal intensive care unit.ResultsPreterm birth (before 37 weeks of gestation) occurred in 49 out of 407 women (12.0%) in the treatment group (resulting in 44 live births) and in 52 out of 405 women (12.8%) in the control group (resulting in 38 live births). Although periodontal treatment improved periodontitis measures (P<0.001), it did not significantly alter the risk of preterm delivery [P 0.70; hazard ratio for treatment group versus control group, 0.93; 95% confidence interval (CI), 0.63-1.37]. There were no significant differences between the treatment and control groups in mean babies' birth weights (3239 g versus 3258 g; P 0.64) or in the rate of delivery of infants who were small for gestational age (12.7% versus 12.3%; odds ratio, 1.04; 95% CI, 0.68-1.58). There were five spontaneous abortions or stillbirths in the treatment group, compared with 14 in the control group (P 0.08).ConclusionsTreatment of periodontitis in pregnant women improves periodontal disease and is safe but does not significantly alter rates of preterm birth, low birth weight or foetal growth restriction.Evidence-Based Dentistry (2007) 8, 5-6. doi:10.1038/sj.ebd.6400486.

McGaw, T. (2002). "Periodontal disease and preterm delivery of low-birth-weight infants." J Can Dent Assoc 68(3): 165-9.

ABSTRACT: Preterm delivery of low-birth-weight infants (PLBW) remains a significant public health issue and a leading cause of neonatal death and long-term neurodevelopmental disturbances and health problems. Recent epidemiological and microbiological immunological studies have suggested that periodontal disease may be an independent risk factor for PLBW. Postulated mechanisms include translocation of periodontal pathogens to the fetoplacental unit and action of a periodontal reservoir of lipopolysaccharides or inflammatory mediators. However, non-causal explanations for the correlation between periodontitis and PLBW can also be offered. Prospective studies, and eventually interventional studies, will be necessary before periodontitis can be considered as a causal factor for PLBW.

Michalowicz, B. S. and R. Durand (2007). "Maternal periodontal disease and spontaneous preterm birth." Periodontol 2000 44: 103-12.

Michalowicz, B. S., J. S. Hodges, et al. (2006). "Treatment of periodontal disease and the risk of preterm birth." N Engl J Med 355(18): 1885-94.

ABSTRACT: BACKGROUND: Maternal periodontal disease has been associated with an increased risk of preterm birth and low birth weight. We studied the effect of nonsurgical periodontal treatment on preterm birth. METHODS: We randomly assigned women between 13 and 17 weeks of gestation to undergo scaling and root planing either before 21 weeks (413 patients in the treatment group) or after delivery (410 patients in the control group). Patients in the treatment group also underwent monthly tooth polishing and received instruction in oral hygiene. The gestational age at the end of pregnancy was the prespecified primary outcome. Secondary outcomes were birth weight and the proportion of infants who were small for gestational age. RESULTS: In the follow-up analysis, preterm birth (before 37 weeks of gestation) occurred in 49 of 407 women (12.0%) in the treatment group (resulting in 44 live births) and in 52 of 405 women (12.8%) in the control group (resulting in 38 live births). Although periodontal treatment improved periodontitis measures (P<0.001), it did not significantly alter the risk of preterm delivery (P=0.70; hazard ratio for treatment group vs. control group, 0.93; 95% confidence interval [CI], 0.63 to 1.37). There were no significant differences between the treatment and control groups in birth weight (3239 g vs. 3258 g, P=0.64) or in the rate of delivery of infants that were small for gestational age (12.7% vs. 12.3%; odds ratio, 1.04; 95% CI, 0.68 to 1.58). There were 5 spontaneous abortions or stillbirths in the treatment group, as compared with 14 in the control group (P=0.08). CONCLUSIONS: Treatment of periodontitis in pregnant women improves periodontal disease and is safe but does not significantly alter rates of preterm birth, low birth weight, or fetal growth restriction. (ClinicalTrials.gov number, NCT00066131 [ClinicalTrials.gov].).

Moore, S., M. Ide, et al. (2004). "An investigation into the association among preterm birth, cytokine gene polymorphisms and periodontal disease." Bjog 111(2): 125-32.

ABSTRACT: OBJECTIVE: To investigate a putative relationship between preterm delivery and the carriage of polymorphic genes that code for the cytokines interleukin-1beta (IL-1beta) at codon +3953 and tumour necrosis factor-alpha (TNF-alpha) at codon -308 in a group of postpartum women and to elucidate if the concurrent presence of periodontal disease increased the risk of preterm delivery in this group. DESIGN: Case-control study SETTING: Postnatal wards at Guy's and St Thomas' Hospital Trust. POPULATION: Postpartum women from southeast London, UK. METHODS: Case subjects were defined as those who experienced a birth at less than 37 weeks of gestation. Control subjects gave birth at term. Demographic data were collected and a periodontal examination was performed. Blood samples were collected and analysed by restriction fragment length polymerase techniques for the presence of each of the allelic variants. MAIN OUTCOME MEASURES: The level of periodontal disease and the carriage of allelic variants of IL-1beta+3953 and TNF-alpha-308 genes. RESULTS: Forty-eight case subjects and 82 control subjects were assessed. There was no statistically significant difference in the carriage of the IL-1beta+3953 allelic variant between cases and controls (29%versus 18%, P= 0.112). However, 23 (48%) of the case subjects and 24 (29%) of controls were heterozygous or homozygous for the variant TNF-alpha-308 gene (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.0-5.0, P= 0.026). There was no association between the carriage of either the polymorphic IL-1beta+3953 or TNF-alpha-308 variant and the severity of periodontal disease. The combination of periodontal disease and the allelic variant did not increase the risk of preterm delivery. CONCLUSIONS: In this study, a higher proportion of women who delivered preterm carried the polymorphic TNF-alpha-308 gene. There did not appear to be any interaction between either of the genotypes and periodontal disease with preterm delivery as has been reported for bacterial vaginosis and the TNF-alpha-308 polymorphic gene.

Nesse, W., F. K. Spijkervat, et al. (2006). "[Links between periodontal disease and general health. 2. Preterm birth, diabetes and autoimmune diseases]." Ned Tijdschr Tandheelkd 113(5): 191-6.

ABSTRACT: The condition of the periodontium may effect people's general health. There is evidence of a correlation between periodontal disease and preterm birth or low birth weight. In pregnant women with periodontal disease, scaling and root planing seems to reduce the risk of preterm birth or low birth weight. Furthermore, periodontal disease appears to have an adverse effect on glycemic control in diabetics. However, periodontal treatment as a means to glycemic control is restricted unless it includes the use of systemic antibiotics. Slowly, a possible correlation between periodontal disease and autoimmune diseases is emerging. Further research into the correlations between periodontal disease and systemic health is desirable and might well result in new therapeutic options.

Noack, B., J. Klingenberg, et al. (2005). "Periodontal status and preterm low birth weight: a case control study." J Periodontal Res 40(4): 339-45.

ABSTRACT: BACKGROUND: Previous studies have suggested that periodontal disease may be an important risk factor for preterm low birth weight. However, the link between periodontal health status of pregnant women and preterm low birth weight is contentious, as recent studies found no association between periodontitis and pregnancy outcome. OBJECTIVE: The aim of this study was to investigate this potential link in a German Caucasian population. METHODS: Fifty-nine pregnant women with a high risk for a preterm low birth weight infant (suffering from preterm contractions, cases, group 1) as well as 42 control women with no preterm contractions during pregnancy and having an infant appropriate for date and weight (>or= 37 weeks gestation, >or= 2500 g, group 2) were examined. Clinical periodontal status was recorded on a full mouth basis. Subgingival plaque samples were taken and periodontal pathogens were identified by polymerase chain reaction. Additionally, interleukin-1 beta level in gingival crevicular fluid was analysed. RESULTS: The mean percentage of sites showing moderate to advanced attachment loss (>or=3 mm) was low in all study groups (group 1: 9.9 +/- 11.2%; group 2:10.6 +/- 14.1%, respectively). No significant differences between the groups in any aspects of the studied periodontitis parameters could be detected. Using a logistic regression model controlling for known preterm low birth weight risk factors, no periodontitis-associated factors increased risk for preterm contractions or preterm low birth weight. The odds ratio (OR) was 1.19 for preterm contractions, the 95% confidence interval (CI) 0.46; 3.11 and 0.73 for preterm low birth weight; 95% CI: 0.13; 4.19, respectively. CONCLUSION: In this population, periodontitis was not a detectable risk factor for preterm low birth weight in pregnant women.

Oertling, K. M. and R. Barsley (2003). "The relationship between periodontal disease and preterm low birth weight and a new Medicaid dental program intervention for pregnant women." Lda J 62(4): 10-3.

Offenbacher, S., K. A. Boggess, et al. (2006). "Progressive periodontal disease and risk of very preterm delivery." Obstet Gynecol 107(1): 29-36.

ABSTRACT: OBJECTIVE: The goal was to estimate whether maternal periodontal disease was predictive of preterm (less than 37 weeks) or very preterm (less than 32 weeks) births. METHODS: A prospective study of obstetric outcomes, entitled Oral Conditions and Pregnancy (OCAP), was conducted with 1,020 pregnant women who received both an antepartum and postpartum periodontal examination. Predictive models were developed to estimate whether maternal exposure to either periodontal disease at enrollment (less than 26 weeks) and/or periodontal disease progression during pregnancy, as determined by comparing postpartum with antepartum status, were predictive of preterm or very preterm births, adjusting for risk factors including previous preterm delivery, race, smoking, social domain variables, and other infections. RESULTS: Incidence of preterm birth was 11.2% among periodontally healthy women, compared with 28.6% in women with moderate-severe periodontal disease (adjusted risk ratio [RR] 1.6, 95% confidence interval [CI] 1.1-2.3). Antepartum moderate-severe periodontal disease was associated with an increased incidence of spontaneous preterm births (15.2% versus 24.9%, adjusted RR 2.0, 95% CI 1.2-3.2). Similarly, the unadjusted rate of very preterm delivery was 6.4% among women with periodontal disease progression, significantly higher than the 1.8% rate among women without disease progression (adjusted RR 2.4, 95% CI 1.1-5.2). CONCLUSION: The OCAP study demonstrates that maternal periodontal disease increases relative risk for preterm or spontaneous preterm births. Furthermore, periodontal disease progression during pregnancy was a predictor of the more severe adverse pregnancy outcome of very preterm birth, independently of traditional obstetric, periodontal, and social domain risk factors. LEVEL OF EVIDENCE: II-2.

Offenbacher, S., V. Katz, et al. (1996). "Periodontal infection as a possible risk factor for preterm low birth weight." J Periodontol 67(10 Suppl): 1103-13.

ABSTRACT: Peridontal diseases are gram-negative anaerobic infections that can occur in women of childbearing age (18 to 34 years). In the present investigation we sought to determine whether the prevalence of maternal periodontal infection could be associated with preterm low birth weight (PLBW), controlling for known risk factors and potential covariates. A case-control study of 124 pregnant or postpartum mothers was performed. PLBW cases were defined as a mother with a birth of less than 2,500 g and one or more of the following: gestational age < 37 weeks, preterm labor (PTL), or premature rupture of membranes (PROM). Controls were normal birth weight infants (NBW). Assessments included a broad range of known obstetric risk factors, such as tobacco use, drug use, alcohol consumption, level of prenatal care, parity, genitourinary infections, and nutrition. Each subject received a periodontal examination to determine clinical attachment level. PLBW cases and primiparous PLBW cases (n = 93) had significantly worse periodontal disease than the respective NBW controls. Multivariate logistic regression models, controlling for other risk factors and covariates, demonstrated that periodontal disease is a statistically significant risk factor for PLBW with adjusted odds ratios of 7.9 and 7.5 for all PLBW cases and primiparous PLBW cases, respectively. These data indicate that periodontal diseases represent a previously unrecognized and clinically significant risk factor for preterm low birth weight as a consequence of either PTL or preterm PROM.

Peretz, B. (2005). "Preterm low birthweight (PLBW) and maternal periodontal disease: a debate in the literature." Refuat Hapeh Vehashinayim 22(1): 88.

Pretorius, C., A. Jagatt, et al. (2007). "The relationship between periodontal disease, bacterial vaginosis, and preterm birth." J Perinat Med 35(2): 93-9.

ABSTRACT: Spontaneous preterm labor leading to preterm birth is a major cause of perinatal mortality and morbidity worldwide. The etiology of spontaneous preterm labor is multifactoral but there is overwhelming evidence to implicate infection in up to 40% of cases. Historically, this infective link has focused on the associations between abnormal genital tract flora in pregnancy (diagnosed by the presence of bacterial vaginosis) and preterm birth. Recently, another condition related to abnormal flora (periodontal disease) has been linked with preterm birth. There are microbiological similarities between the oral cavity and the female genital tract giving rise to a possible common pathophysiology. This review records the interrelationship between periodontal disease, bacterial vaginosis, and preterm birth. We postulate on the mechanism linking the three conditions, particularly through microbiology and gene-environmental interactions. Periodontal disease and bacterial vaginosis may be risk factors in their own rights or may be interrelated. We speculate on whether periodontitisis a marker for an immune hyperresponse to abnormal flora which in the oral cavity results in periodontitis and in the case of bacterial vaginosis might result in preterm birth. We also postulate on the risk of preterm birth by periodontitis alone, bacterial vaginosis alone, or both.

Radnai, M. and I. Gorzo (2002). "[Periodontal disease as a potential risk factor for preterm birth and low birth weight (Literature review)]." Fogorv Sz 95(6): 241-4.

ABSTRACT: In Hungary the number of low birth-weight new-born babies is about 8200 in a year, while the frequency of for preterm birth is 8.2%. The infant mortality among the low birth-weight babies is higher, than among the normal weight babies. Every efforts are used to decrease the number of preterm births. Researches have been carried out since decades on finding its possible risk factors. A possible risk factor for low birth-weight babies may be the chronic periodontal infection. The publication provides a review of recently published evidences of the potential association between periodontal infection and preterm low birth-weight.

Radnai, M., I. Gorzo, et al. (2006). "Possible association between mother's periodontal status and preterm delivery." J Clin Periodontol 33(11): 791-6.

ABSTRACT: BACKGROUND: A case-control study was undertaken to detect whether initial chronic localized periodontitis could be a risk factor for preterm birth (PB) and foetal growth restriction. METHODS: A PB case was defined if a patient had a threatening premature event during pregnancy pre-term premature rupture of membranes, or spontaneous pre-term delivery, before the 37th week of pregnancy, and/or the weight of the newborn was <2500 g. Into the PB (case) group, 77 women were allocated, while 84 were included in the control group, all of whom had delivery after the 37th gestational week and with a newborn weighing >or=2500 g. RESULTS: A significant association was found between PB and initial chronic localized periodontitis, the criteria being bleeding at >or=50% of the examined teeth and having at least at one site at >or=4 mm probing depth (p=0.0001). The adjusted odds ratio for initial chronic localized periodontitis was 3.32, 95% CI: 1.64-6.69. The average weight of newborns of mothers with periodontitis was significantly less than that of the women without periodontitis (p=0.002). CONCLUSIONS: The results support the hypothesis that initial chronic localized periodontitis of pregnant women could lead to PB, and birth-weight reduction.

Riche, E. L., K. A. Boggess, et al. (2002). "Periodontal disease increases the risk of preterm delivery among preeclamptic women." Ann Periodontol 7(1): 95-101.

ABSTRACT: BACKGROUND: Preterm births are a major cause of neonatal morbidity and mortality, and represent an important public health issue. About 30% of preterm births are due to medical conditions of the mother or the fetus, among "which preeclampsia plays a major role. We have previously reported that maternal periodontal disease enhances the risk for preterm delivery and preeclampsia. Our current objective was to determine whether maternal periodontal disease increases the risk for preterm delivery among preeclamptic women. METHODS: Women were enrolled prior to their twenty-sixth week of gestation. Periodontal status was assessed at baseline and defined as healthy, mild, or moderate/severe. Repeat examinations were performed at delivery to assess changes in periodontal status. RESULTS: A cohort of 1,020 women was studied, 47 of whom had preeclampsia. A strong association between periodontal disease status at enrollment and rate of premature delivery was observed among preeclamptic women after adjusting for the major risk factors for preterm delivery, including maternal race; age; marital status; WIC (women, infants, children program) or food stamps; insurance; previous preterm delivery; and chorioamnionitis. Among preeclamptic women, 49.3% with mild periodontal disease and 82.6% with moderate to severe disease delivered preterm (hazard ratios [HR] 4.11 and 11.0, respectively). Periodontal disease worsening during pregnancy in preeclamptic women was also associated with an increased risk of preterm births (HR 8.44). CONCLUSION: These results suggest that mothers with preeclampsia may be at greater risk for preterm delivery if periodontal disease is present early in pregnancy or progresses during pregnancy.

Russell, S. and A. P. Dasanayake (2006). "Maternal periodontal disease is related to preterm low birth weight delivery in a group of Brazilian women." J Evid Based Dent Pract 6(3): 236-7.

Russell, S. and A. P. Dasanayake (2006). "Periodontal status is unrelated to preterm low birth weight in a group of Caucasian German women." J Evid Based Dent Pract 6(3): 240-1.

Sanchez, A. R., S. Bagniewski, et al. (2007). "Correlations between maternal periodontal conditions and preterm low birth weight infants." J Int Acad Periodontol 9(2): 34-41.

ABSTRACT: OBJECTIVE: The goal of this cross-sectional study was to assess the correlation between periodontal conditions of pregnant women and characteristics of the infant at birth. METHODS: One hundred thirteen pregnant patients received a thorough dental and periodontal examination and questionnaire. Probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), and calculus index (CI) were recorded. Patients were classified as to whether they had periodontitis (presence of 2 or more teeth with 1 or more sites experiencing CAL > or = 3 mm and PD > or = 4 mm at the same site), gingivitis (> or = 25% of sites with BOP), or healthy periodontium. Patients were followed to ascertain information on pregnancy-related complications, gestational age, and birth weight. Miscarriages and infants born as single births at < 37 weeks or weighing < 5.5 pounds were classified as preterm low birth weight (PT/LBW) infants. The periodontal clinical parameters were compared between groups using the Kruskal-Wallis test and the Wilcoxon rank sum test. Spearman rank correlation coefficients were calculated to estimate the correlations. RESULTS: Of the 113 pregnant patients, outcome data were available on 111 patients. In addition, data from one patient who delivered twins and two patients who had miscarriages were not considered in the correlation analyses. The prevalence of periodontitis and gingivitis in this population was 23.9% and 54%, while the prevalence of PT/LBW infants was 19%, 7%, and 13% among the patients with periodontitis, gingivitis, and healthy periodontium, respectively. Given the small number of patients with PT/LBW infants, we were unable to identify any statistically significant associations between the periodontal clinical parameters and PT/LBW, although the data suggested the trend that patients with PT/LBW infants were more likely to have poorer probing depths (median number of sites with PD > or = 4mm, 13 vs. 6; p = 0.19). Among the 108 single births, birth weight was negatively correlated with maternal mean PD in the periodontitis group (r = -0.37, p = 0.055), and the percentage of sites with BOP in the mandible (r = -0.32, p = 0.014), total CL (r = -0.31, p = 0.01 7) and maxillary arch CI (r = -0.29, p = 0.025) in the gingivitis group. CONCLUSION: Infant birth weight showed moderate relationships with maternal periodontal conditions in subjects with periodontal diseases.

Sanchez, A. R., L. I. Kupp, et al. (2004). "Maternal chronic infection as a risk factor in preterm low birth weight infants: the link with periodontal infection." J Int Acad Periodontol 6(3): 89-94.

ABSTRACT: In the past decade, there has been mounting scientific evidence suggesting that periodontal disease may play an important role as a risk factor for adverse pregnancy outcomes. This article focuses on the definition, incidence, risk factors associated with preterm low birthweight infants (PLBW), the evidence linking chronic infections and PLBW, and the scientific evidence linking periodontal infections with adverse pregnancy outcomes. Additionally, this review summarizes the current epidemiological studies on the PLBW/infection relation and makes conclusions based on these results. Data from a limited number of studies available support the hypothesis that periodontal disease may act as a risk factor for PLBW infants. The fetal exposure to different periodontal pathogens needs to be confirmed, the mechanisms associated with the potential passage of periodontal bacteria across the placental barrier, and the efficacy of different periodontal treatments in reducing the risk for PLBW need to be studied further.

Stamilio, D. M., J. J. Chang, et al. (2007). "Periodontal disease and preterm birth: do the data have enough teeth to recommend screening and preventive treatment?" Am J Obstet Gynecol 196(2): 93-4.

Vergnes, J. N. and M. Sixou (2007). "Preterm low birth weight and maternal periodontal status: a meta-analysis." Am J Obstet Gynecol 196(2): 135 e1-7.

ABSTRACT: OBJECTIVE: This study was undertaken to assess the effect of maternal periodontal disease on preterm delivery and/or birth of low-weight infants. STUDY DESIGN: We conducted a meta-analytic review of 5 medical databases (MEDLINE, EMBASE, LILACS, BIOSIS and PASCAL) for human observational studies linking preterm delivery and/or birth of low-weight infants to maternal periodontal disease. The MOOSE guidelines for meta-analysis of observational studies were followed. RESULTS: The literature search revealed 17 articles that met the inclusion criteria. Seven thousand one hundred fifty-one women participated in the studies, 1056 of whom delivered a preterm and/or low birthweight infant. The overall odds ratio was 2.83 (95% CI: 1.95-4.10, P < .0001). This pooled value needed to be interpreted cautiously because there appeared to be a clear trend for the better quality studies to be of lower association strength. CONCLUSION: These findings indicate a likely association, but it needs to be confirmed by large, well-designed, multicenter trials.

Watts, T. (2002). "Maternal periodontal disease and preterm low birthweight: case-control study." Br Dent J 193(5): 267.

Wood, S., A. Frydman, et al. (2006). "Periodontal disease and spontaneous preterm birth: a case control study." BMC Pregnancy Childbirth 6: 24.

ABSTRACT: BACKGROUND: Several studies have suggested an association between periodontal disease and prematurity but this finding has not been consistently observed. METHODS: Case control study. Cases (n = 50) were women who had delivered after spontaneous preterm labor at <35 weeks gestation. Two groups of controls (n = 101) were recruited: women who were undelivered but at a preterm gestation and women who delivered at term. A standard, clinical, periodontal examination was performed and gingival crevicular fluid was obtained from standardized locations and tested for neutrophil elastase along with the bacterial enzymes gingipain and dipeptidylpeptidase. Data were analyzed with Fisher's exact tests, ANOVA and multivariate logistic regression. RESULTS: There was no difference in the proportion of sites with significant attachment loss (> or =3 mm): Cases-3.2%, Controls-2.2% p = 0.21. The gingival crevicular fluid concentrations of elastase and gingipain were elevated in cases vs. controls 238.8 uU/ul vs. 159.6 uU/ul p = .007 and 2.70 uU/ul vs. 1.56 uU/ul p = .001. On multivariate analysis, the mean log concentration of elastase, but not of gingipain, remained a significant predictor of preterm labor p = .0.015. CONCLUSION: We found no evidence that clinical periodontal disease is associated with spontaneous preterm birth. Elevated gingival crevicular fluid levels of elastase were associated with preterm birth but further research is needed before this can be assumed to be a causal relationship.

Zachariasen, R. D. and D. K. Dennison (1998). "Periodontal disease and preterm low birth weight deliveries." J Gt Houst Dent Soc 70(4): 16-9.

Zadeh-Modarres, S., B. Amooian, et al. (2007). "Periodontal health in mothers of preterm and term infants." Taiwan J Obstet Gynecol 46(2): 157-61.

ABSTRACT: OBJECTIVE: Recent studies have suggested that chronic periodontitis may induce an inflammatory response which can cause premature delivery. This study was designed to assess the association between periodontal health and preterm labor in Iranian female population. MATERIALS AND METHODS: In this case-control study, 201 pregnant women without systemic disease or other risk factors for preterm labor were chosen. The control group (n = 99) had term labor (infants > or =37 weeks) and the case group (n = 102) had preterm labor (infants < 37 weeks). Bleeding index, pocket depth and debris index were measured. RESULTS: The data of bleeding index (cases, 0.64 +/- 0.38; controls, 0.57 +/- 0.35), probing depth (cases, 2.80 +/- 0.30; controls, 1.63 +/- 0.23) and debris index (cases, 1.38 +/- 0.67; controls, 0.81 +/- 0.38) revealed a statistically significant difference between the two groups (p < 0.05). CONCLUSION: According to the findings of this study, there is a noticeable relationship between periodontal health and duration of pregnancy; periodontal disease could be a risk factor for preterm labor. Oral hygiene is strongly recommended to be included in prenatal care.