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Adverse Birth Outcomes and Oral Health

This literature review investigates the evidence surrounding the association between periodontal disease and preterm births and low birth weight.

This course was published in the September 2017 issue and expires September 2020. The authors have no commercial conflicts of interest to disclose. This 2 credit hour self-study activity is electronically mediated.



After reading this course, the participant should be able to:

  1. Identify the relationship between oral health and systemic health.
  2. Define adverse birth outcomes and identify risk factors.
  3. Explain the relationship between maternal periodontitis and adverse birth outcomes.
  4. Discuss the safety and importance of dental treatment during pregnancy.

Optimal oral health is critical to the overall health of pregnant women and their babies. Untreated maternal oral conditions can be a major risk factor for health complications in the developing fetus or newborn infant.1,2 However, oral health is often overlooked in the scope of comprehensive prenatal care.3 For instance, approximately 22% to 34% of women in the United States seek treatment or preventive care from a dentist during pregnancy.3,4

Maternal periodontal disease has been associated with preterm birth, development of preeclampsia and gestational diabetes, and delivery of low-birth weight (LBW) infants. The transfer of maternal oral bacteria to newborn infants may also predispose them to dental caries.4,5 Both periodontal diseases and dental caries are highly prevalent in women of child-bearing age, particularly among low-income women and members of certain racial and ethnic minority groups.4,5 According to research, 38.4% of US women age 30 and older have some form of periodontal disease, with 65.4% of those living below the federal poverty level.6 One recent study identified a 73.9% prevalence of periodontal diseases among women age 18 to 40.In 2012, 25.9% of women between the ages of 20 and 44 had untreated dental caries, an increase of 4.1% since 2008. Of the 25.9%, 41.4% were African American and 35.7% were Hispanic.8 Consequently, oral health professionals and prenatal providers need to emphasize the importance of receiving professional oral health care during pregnancy and educate pregnant women about oral disease prevention.1,2,4,5,9–13 

Since 2000, research has identified the presence of multiple oral bacterial species in locations outside of the oral cavity. Streptococcus mutans (brain abscess), Aggregatibacter actinomycetemcomitans (bacterial endocarditis), and A. actinomycetemcomitans and Porphyromonas gingivalis (atherosclerotic plaques in the aorta) have all been discovered throughout the body, substantiating the relationship between oral health and systemic health.13 Preterm birth, LBW infants, and periodontal diseases all have biological, social, and behavioral determinants that can increase the likelihood of occurrence.2,14 Studying the direct effect of any one risk factor on the outcomes of preterm birth and LBW babies is challenging because of the many confounding variables that may generate the same outcome.14 However, it is clear that the status of individuals’ oral ­conditions affects their systemic health and possibly the success of a pregnancy and health of their infants.


Preterm birth and LBW are major causes of infant mortality and morbidity both in the US and around the world. They continue to be a significant public health issue despite many attempts by multiple public health entities to reduce their prevalence.15–18 In 2012, 450,000 babies were born preterm in the US, accounting for 35% of all infant deaths.19 In 2015, 8% of all infants born in the US were LBW. The prevalence of LBW is higher among non-Hispanic black infants (13.2%) and Puerto Rican infants (9.5%) than among infants of any other racial or ethnic group.8 The World Health Organization estimates that 15 million babies are born preterm every year around the globe. This adverse birth outcome is the leading cause of death among children younger than 5.20 Approximately seven out of 10 LBW babies are born prematurely.21 Preterm birth refers to infants born before 37 weeks of gestation19 and LBW is defined as birth weight less than 2,500 grams (5.5 pounds).21

The gestational age of infants is the most important predictor of their subsequent health and survival.22 Premature infants have a greater risk of feeding difficulties, respiratory distress, and delayed brain development, as well as lifelong health complications, such as vision problems, developmental delays, deafness, and poor motor skills.2,4,5,17,22–24 Babies born at a LBW may be more likely than infants born at a normal weight to develop certain health conditions later in life, including diabetes, heart disease, and high blood pressure.21

There are multiple causes for adverse pregnancy outcomes. In many cases, preterm births can be attributed to infection or other chronic systemic conditions (diabetes and/or high blood pressure).20 However, in approximately 50% of preterm births, the direct cause is not immediately known.13 Some factors that may cause preterm birth include a history of premature births, chronic health conditions (high blood pressure, preeclampsia, diabetes), insufficient maternal weight gain during pregnancy, smoking, alcohol consumption, use of illegal drugs/abuse of prescription drugs, stress, and belonging to a certain racial/ethnic group (African-American).13,25–27

The high prevalence of preterm births and LBW infants emphasizes the need to reduce or eliminate risk factors that may contribute to their occurrence. This includes acknowledging the possible relationship of these adverse pregnancy outcomes with untreated maternal periodontal disease and incorporating oral health practice guidelines into routine obstetrical care.


During pregnancy, changes in hormone levels promote an inflammatory response that increases the risk of developing gingivitis and periodontitis.5,13 Pregnancy-induced gingivitis—the most common oral disease in pregnancy—may manifest as gingival inflammation, erythema, and bleeding (spontaneous or after manipulation).1 The majority of pregnant women may experience gingivitis due to pregnancy-related hormonal changes.3,13,28 Various studies have identified a large range regarding the prevalence of pregnancy gingivitis, from 36% in one study to 100% in another.3,13,28 Differences in study design and demographics of study participants may account for these considerable variations.

The destructive process of periodontitis involves both direct tissue damage resulting from the presence of bacteria surrounding the teeth and their adjacent structures, as well as indirect damage caused by the host’s inflammatory response.13,15,17,29,30 The systemic inflammation caused by periodontal infection and bacterial colonization in the oral cavity may play a role in adverse pregnancy outcomes.31 Researchers hypothesize that periodontal pathogens (inflammatory mediators) reach the maternal reproductive system through the bloodstream and cause an inflammatory cascade, triggering a second round of inflammatory responses.13–15,29,31–33 Eventually, the bacteria, virulence factors, and inflammatory cytokines reach the placenta and create a new bacterial infection, initiating an inflammatory response at the fetal-placental interface.13,30,34,35 As more inflammatory cytokines are produced, tissue destruction can occur, affecting the structural integrity of the placenta.13,30,32,35 These cytokines are related to the onset of labor, inducing tenderness of the uterine muscles, stimulating uterine contractions and cervical dilation, and, consequently, triggering preterm birth.13,30,35

In some cases of preterm birth, elevated levels of these cytokines have been found in the amniotic fluid.30 One study discovered P. gingivalis, a pa­thogen observed in periodontitis, in the amniotic fluid of women with threatened premature labor.36 Researchers found that the P. gingivalis antigens were numerous in the placental tissues, strengthening the theory of bacterial migration from oral cavity to the fetus.36 Other studies have successfully isolated the anaerobic microbe, Fusobacterium nucleatum, from the amniotic fluid, placenta, and chorio-amnionic membranes of women delivering premature­ly.14,31,35–40 Another study identified P. gingivalis and A. actinomycetemcomitans in the amniotic fluid of women with active periodontitis.14 Studies have discovered a statistically significant relationship be­tween the presence of active maternal periodontal disease and premature birth and/or LBW.2,18,28,41–45 

In 2016, Corbella et al15 published a systematic review that measured the potential association between adverse birth outcomes and periodontitis. The authors examined and analyzed case-control and prospective cohort studies (n=22). Upon investigating the studies’ characteristics (total number of subjects, mean age of subjects, and definition of periodontal disease), control of possible confounders, and risk of bias, the researchers concluded that periodontitis may be a risk factor for preterm birth, LBW, and preterm LBW; although the association was low. The authors concluded that while a low association between periodontitis and adverse birth outcomes had been identified, more research is needed to identify a more definitive causal relationship, as well as to measure the effect of nonsurgical periodontal therapy and the reduction in adverse birth outcomes.15

Other studies and systematic reviews have revealed contradictory results.16,44,46–50 Vettore et al50 performed a case-control study among post-partum women (n=542) to compare periodontal health status with birth outcomes. They concluded that periodontal diseases did not increase the risk of preterm LBW according to 15 measures of periodontal disease. Another study also assessed whether the presence of periodontitis impacted adverse birth outcomes.51 Researchers conducted a prospective cohort study on pregnant women (n=73) who were between 28 weeks and 36 weeks gestation. Among this study population, periodontitis was not shown to be a risk factor for preterm delivery or a LBW infant.51 Probable reasons for these discrepancies could be the differences in study definitions and methods of diagnosis for preterm birth, preterm LBW, or periodontitis, as well as disparities in confounder controls, study participant demographics, and numbers.13,17 

Studies performed on the effect of nonsurgical treatment of periodontitis in pregnant women and its impact on reducing rates of preterm births or LBW infants have revealed different results. Fiorini et al52 and Kaur et al53 documented that while periodontal treatment improved clinical oral conditions and decreased inflammatory markers, there was no significant decrease in the incidence of adverse birth outcomes. Other studies have found a reduced prevalence of preterm births after treating severe periodontitis in pregnant women.13,54–57 However, studies performed by Xiong et al,58 Horton et al,59 and Han60 observed no positive effect of periodontal treatment on reducing adverse birth outcomes. Similar to the lack of definitive research concerning the causal relationship between periodontitis and preterm births/LBW infants, researchers hypothesize that these conflicting data are also due to the inconsistent study definitions used to classify disease and the possible lack of control in the studies for other factors, such as smoking, maternal age, and ethnicity.13


In 2012, the National Maternal and Child Oral Health Resource Center published Oral Health Care During Pregnancy: A National Consensus Statement. This report, in addition to statements by the American Academy of Periodontology and the American College of Obstetricians and Gynecologists, documents the necessity and importance of maintaining maternal oral health during pregnancy, as well as promoting a collaborative effort between prenatal providers and oral health practitioners to provide oral health education, preventive care, and dental treatment during the gestational period.61,61–64

Most important, these consensus statements aim to reassure the safety of preventive care and therapeutic treatment during pregnancy. Radiographic exposures (with proper shielding of the thyroid and abdomen) for diagnostic procedures do not pose any harmful risk to the developing embryo or fetus and are considered safe throughout the entire pregnancy.12,62 Routine prophylaxis, scaling and root planing, restorative procedures, and local anesthesia administration are also considered safe and may be performed on women at any time during pregnancy.12,62­­–64


This literature review indicates that periodontitis is an oral disease that may have an adverse effect on birth outcomes, including preterm births and LBW infants. Although there is inconclusive research relating to the treatment of periodontitis and its effect on improving birth outcomes, the maintenance of oral health during pregnancy significantly decreases the maternal bacterial load in the oral cavity, improving overall health.13 Also, while the link between oral pathogens and systemic health has been documented,13,14,31,35–40,65 there is still further need to definitively link periodontal diseases with adverse birth outcomes in order to more successfully manage chronic disease and promote maternal and child health.


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  2. Govindaraju P, Venugopal S, Shivakumar MA, Sethuraman S, Ramaiah SK, Mukundan S. Maternal periodontal disease and preterm birth: A case-control study. J Indian Soc Periodontol. 2015;19:512–515.
  3. Silk H, Douglass AB, Douglass JM, Silk L. Oral health during pregnancy. Am Fam Physician. 2008;77:1139–1144.
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  14. Ercan E, Eratalay K, Deren O, et al. Evaluation of periodontal pathogens in amniotic fluid and the role of periodontal disease in pre-term birth and low birth weight. Acta Odontol Scand. 2013;71:553–559.
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  28. Reza Karimi M, Hamissi JH, Naeini SR, Karimi M. The relationship between maternal periodontal status of and preterm and low birth weight infants in iran: A case control study. Glob J Health Sci. 2015;8:184–188.
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  30. Vogt M, Sallum AW, Cecatti JG, Morais SS. Periodontal disease and some adverse perinatal outcomes in a cohort of low risk pregnant women. Reprod Health. 2010;7:29.
  31. Merglova V, Koberova-Ivancakova R, Broukal Z, Dort J. The presence of cariogenic and periodontal pathogens in the oral cavity of one-year-old infants delivered pre-term with very low birthweights: A case control study. BMC Oral Health. 2014;14:109.
  32. Bobetsis YA, Barros SP, Offenbacher S. Exploring the relationship between periodontal disease and pregnancy complications. J Am Dent Assoc. 2006;137(Suppl):7S–13S.
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  34. Yeo BK, Lim LP, Paquette DW, Williams RC. Periodontal disease—the emergence of a risk for systemic conditions: Pre-term low birth weight. Ann Acad Med Singapore. 2005;34:111-116.
  35. Madianos PN, Bobetsis YA, Offenbacher S. Adverse pregnancy outcomes and periodontal disease: Pathogenic mechanisms. J Periodontol. 2013;84(Suppl 4):S170–S180.
  36. Katz J, Chegini N, Shiverick KT, Lamont RJ. Localization of P. gingivalis in preterm delivery placenta. J Dent Res. 2009;88:575–578.
  37. Barak S, Oettinger-Barak O, Machtei EE, Sprecher H, Ohel G. Evidence of periopathogenic microorganisms in placentas of women with preeclampsia. J Periodontol. 2007;78:670–676.
  38. Leon R, Silva N, Ovalle A, et al. Detection of porphyromonas gingivalis in the amniotic fluid in pregnant women with a diagnosis of threatened premature labor. J Periodontol. 2007;78:1249–1255.
  39. Swati P, Thomas B, Vahab SA, Kapaettu S, Kushtagi P. Simultaneous detection of periodontal pathogens in subgingival plaque and placenta of women with hypertension in pregnancy. Arch Gynecol Obstet. 2012;285:613–619.
  40. Gonzales-Marin C, Spratt DA, Millar MR, Simmonds M, Kempley ST, Allaker RP. Levels of periodontal pathogens in neonatal gastric aspirates and possible maternal sites of origin. Mol Oral Microbiol. 2011;26:277–290.
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  44. Heimonen A, Janket SJ, Kaaja R, Ackerson LK, Muthukrishnan P, Meurman JH. Oral inflammatory burden and preterm birth. J Periodontol. 2009;80:884–891.
  45. Mathew RJ, Bose A, Prasad JH, Muliyil JP, Singh D. Maternal periodontal disease as a significant risk factor for low birth weight in pregnant women attending a secondary care hospital in south india: A case-control study. Indian J Dent Res. 2014;25:742–747.
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  50. Vettore MV, Leal M, Leao AT, da Silva AM, Lamarca GA, Sheiham A. The relationship between periodontitis and preterm low birthweight. J Dent Res. 2008;87:73–78.
  51. Ali T, Abidin K. Relationship of periodontal disease to preterm low birth weight infants in a selected population- a prospective study. Community Dent Health. 2012;29:100–105.
  52. Fiorini T, Susin C, da Rocha JM, et al. Effect of nonsurgical periodontal therapy on serum and gingival crevicular fluid cytokine levels during pregnancy and postpartum. J Periodontal Res. 2013;48:126­–133.
  53. Kaur M, Geisinger ML, Geurs NC, et al. Effect of intensive oral hygiene regimen during pregnancy on periodontal health, cytokine levels, and pregnancy outcomes: A pilot study. J Periodontol. 2014;85:1684–1692.
  54. Jeffcoat M, Parry S, Sammel M, Clothier B, Catlin A, Macones G. Periodontal infection and preterm birth: Successful periodontal therapy reduces the risk of preterm birth. BJOG. 2011;118:250–256.
  55. Lopez NJ, Da Silva I, Ipinza J, Gutierrez J. Periodontal therapy reduces the rate of preterm low birth weight in women with pregnancy-associated gingivitis. J Periodontol. 2005;76(Suppl 11):2144–2153.
  56. Offenbacher S, Lieff S, Boggess KA, et al. Maternal periodontitis and prematurity. part I: Obstetric outcome of prematurity and growth restriction. Ann Periodontol. 2001;6:164–174.
  57. Offenbacher S, Lin D, Strauss R, et al. Effects of periodontal therapy during pregnancy on periodontal status, biologic parameters, and pregnancy outcomes: A pilot study. J Periodontol. 2006;77:2011–2024.
  58. Xiong X, Buekens P, Goldenberg RL, Offenbacher S, Qian X. Optimal timing of periodontal disease treatment for prevention of adverse pregnancy outcomes: Before or during pregnancy? Am J Obstet Gynecol. 2011;205:111.
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Featured photo by MICZ123/E+/GETTY IMAGES PLUS 

From Dimensions of Dental Hygiene. September 2017;15(9):44-47-49.

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