Pregnancy Outcomes

Up to 30% of the general population has a genetic predisposition to periodontitis.¹ In women, the incidence of periodontitis changes with age. A minimum of 23% of women between the ages of 30 and 54 have periodontitis.¹ In more mature women (ages 55-90) with dentition, the percentage increases to at least 44%.¹
Many female hormonal fluctuations—puberty, menstruation, pregnancy, and menopause—can affect the gingiva and the body’s ability to fight periodontitis.¹ During pregnancy, the health and well-being of the mother and fetus are monitored through examinations and tests. The literature suggests that any maternal infection, including periodontitis, may be considered a potential danger to the mother and fetus.¹

Typically, a pregnancy lasts around 40 weeks. A pregnancy that ends prior to 37 weeks is considered preterm. In the United States, approximately 12% of pregnancies are complicated by a preterm birth.^2-4 The causes for preterm birth may be triggered by the body’s response to certain infections, such as those in the amniotic fluid and fetal membranes. However, nearly one half of all cases have no known etiology.^2-4

A low birth weight infant weighs less than 5 pounds 8 ounces (2,500 grams). The incidence of low birth weight ranges from 4%-15% worldwide.^2-4 In the Unites States, the incidence dramatically increased from 6.9% to 7.6% between 1987 and1999.^2-4 This rise represents a significant increase in health care dollars—estimated at 5.5 billion annually.^2-4 Each gram of fetal weight under 2,500 grams represents an increased cost of $75 per day in neonatal intensive care expenses.^2-4 For this reason alone, decreasing the incidence of prematurity and low birth-weight infants is an overall benefit. However, the most important reason is to lessen neonatal morbidity and mortality.

PERIODONTITIS AND PREMATURITY

In periodontitis, predominately gram-negative anaerobic and microaerophilic bacteria colonize subgingivally, resulting in the inflammation of gingival and periodontal tissue. This inflammatory process can cause alveolar bone destruction. Tissue destruction occurs because of the activation of immune cells by the cell wall component of the microorganisms. These immune cells stimulate the production of host-derived enzymes, such as cytokines and other pro-inflammatory mediators, resulting in connective tissue destruction. Cytokines or biochemical markers specifically found in periodontitis are PGE2, TNFa, IL-1b, IL-6, MMPs, and LPS. These same biochemical mediators help mediate uterine contractions; cervical dilation; and labor, which can result in a preterm delivery, a low birth weight infant, and, ultimately, neonatal morbidity.

Common risk factors for periodontitis and preterm birth or low birth weight infants include: race, low socioeconomic status, low educational levels, and tobacco, drug, and alcohol use.⁵ Other risk factors are: previous preterm birth, first pregnancy, and maternal infection. We also know that 30% of people are genetically predisposed to periodontitis. Therefore, it is crucial for women to improve their gingival health. The role of the dental team is to educate patients on ways to improve their oral conditions and systemic health.

GINGIVAL HEALTH AND PREGNANT PATIENT

In the past 10 years, both medical and dental professionals have become more aware of the role the oral cavity plays in the overall health of patients. Therefore, it is more widely accepted that monitoring the gingival status of pregnant women may impact their pregnancy outcomes.

While reviewing the literature, understanding the study design is important. Case control studies are typically done after the event of interest has occurred. Many studies relating to periodontitis and pregnancy are done after the delivery of the infant, therefore the periodontal condition of the mother is unknown prior to delivery. For all case control studies, the primary weakness is that the experimental design does not demonstrate causality. However, prospective studies offer the advantage of studying the cause-effect relationship and are designed prior to participant recruitment. Participants are enrolled before knowing the area of interest of the study. For periodontal disease and pregnancy, the study visits occur prior to delivery of the infant, therefore helping reduce study bias.

Many of the earlier case control studies looked at the gingival tissue response, the amount and make-up of the plaque, and the gingival inflammatory mediators response to pregnancy and then compared these to pregnancy outcomes. These studies identified that women with periodontitis were seven times more likely to deliver a preterm or low birth weight infant.^6-7 They also determined that PGE2 levels were significantly higher in mothers who delivered a preterm or low birth weight infant when compared to a woman who delivered a full term, normal birth weight infant, and that these women also had higher levels of B. Forsythus, P. Gingivalis, A. a., and T. denticola bacteria, which are known to be destructive and part of periodontal biofilm.^5,6

Another case control study looked at preterm delivery and low birth weight infants in London. Within this population, the study was unable to show any relationship between periodontitis and adverse pregnancy outcomes.⁷ In fact, the study reported that the risk of preterm birth and low birth weight infants decreased with increased pocket depth.⁷ These dissimilar results may be due to the population studied and the lack of racial diversity in the London study. In another prospective study, investigators were able to demonstrate that women with periodontitis between the gestational ages of 21 and 24 weeks were more likely to have a preterm birth, with an odds ratio of 4.45 to 7.07 based on gestational age.⁸

In more recent studies, the relationship between periodontal disease and pregnancy outcomes has varied. Two population-based, cross-sectional studies—one done in Brazil and the other in Germany—failed to identify a relationship between periodontal disease in the mother and low birth weight.^8,10 The Brazilian study initially found an association with periodontal disease and prematurity but after adjusting for other maternal variables, the association disappeared.⁹ The German study consisted of only Caucasian women.^8,10

However, other recent studies have identified some relationship between periodontitis and prematurity or low birth weight. One study found that women with early localized periodontitis, defined as at least 50% bleeding and at least one site with pocket depths >4 mm, had an odds ratio of 5.46 for a preterm birth.¹¹ Dortbudak et al identified that women who delivered a preterm infant had more colony-forming units for periodontal pathogens present in their subgingival plaque and significantly higher levels of cytokines PGE2 and IL-6 in the amniotic fluid. They concluded that chronic periodontitis can induce a primary host chorioamniotic response (a bacterial infection of the membrane that forms the fluid filled sac around the fetus) that increases the risk of preterm birth.¹²

A study by Jarjoura et al demonstrated that women who delivered a preterm infant were more likely to have a greater mean attachment loss and a higher prevalence of periodontitis when compared to mothers who delivered full term infants.¹³ Moss et al determined that bleeding upon probing at enrollment and pocket depths greater than 4 mm were found to be significant predictors of periodontal disease in pregnant women.¹⁴ These are but a few of the more recent studies finding that periodontal disease may be an independent risk factor for preterm delivery or low birth weight infants similar to other known risk factors.

DETERMINING CAUSE AND EFFECT

While many of these studies provided evidence that a relationship may exist between periodontal disease and low birth weight or prematurity, none established a cause and effect between the two. Treatment studies help identify if cause and effect exist and a few have been conducted. Lopez et al treated participants with gingivitis by performing an oral prophylaxis prior to 28 weeks gestation and followed up with maintenance treatment every 2-3 weeks until delivery. The second treatment group consisted of participants with periodontitis who received oral prophylaxis after delivery and any rescue treatment necessary during pregnancy. This study determined that the incidence of preterm birth or low birth weight infants was significantly higher in the periodontitis group versus the gingivitis group. The conclusion was that periodontitis was associated with preterm birth and low birth weight infants independent of other risk factors.¹⁵

A second study by Lopez et al randomized participants to either treatment during pregnancy prior to 28 weeks or treatment after delivery. The incidence of preterm birth or low birth weight was 1.84% in the treatment group and 10.11% in the control group. This study concluded that periodontitis appears to be an independent risk factor for preterm birth and low birth weight and that periodontal therapy significantly reduces the rates of both.¹⁶ In another treatment study by Jeffcoat et al, the participants were stratified into one of three treatment groups: scaling and root planing plus antibiotic therapy, scaling and root planing plus a placebo capsule, and oral prophylaxis plus placebo capsule. This study also had an untreated reference group. They concluded that scaling and root planing in pregnant women with periodontitis may reduce the rate of preterm birth and that adjunctive antibiotic therapy did not improve the pregnancy outcome.¹⁷

Currently, two National Institute of Health (NIH)-funded studies are exploring the effects of periodontal treatment on pregnant women with periodontitis. Obstetrics and Periodontal Therapy (OPT) is a multicentered randomized clinical trial. This trial sought to enroll 816 women at four clinical sites. Participants were randomly assigned to receive scaling and root planing either prior to 20 weeks gestation or soon after delivery. All participants were monitored for progression of periodontitis. The primary birth outcome is to determine if periodontal treatment of pregnant patients with periodontitis affects gestational age and the secondary outcome is birth weight. Since the trial is in the follow-up stage of enrolled participants, no data are available at this time.¹⁸

The second NIH-funded trial is Maternal Oral Therapy to Reduce Obstetric Risk (MOTOR). This trial is a multicentered randomized clinical trial seeking to enroll 1,800 women at three clinical performance sites. The primary outcome for MOTOR is the effects of periodontal therapy on the rate of preterm birth <37 week gestation. The secondary outcomes are: the effect of periodontal therapy on the rate of preterm birth <35 weeks gestation, mean birth weight of infants <37 weeks, and neonatal morbidity and mortality. In MOTOR, women are randomly assigned to scaling and root planing in the second trimester or within 4 weeks postpartum. Both groups receive obstetric and dental monitoring during their pregnancy. This study is in year 3 of 5 years. Information from these trials will increase the body of knowledge on the effects of periodontitis and pregnancy outcomes.¹⁸

APPLICATIONS FOR DENTAL PROFESSIONALS

What this research means for the clinical practice of dentistry and dental hygiene is multifaceted. For oral health care professionals, caring for patients’ well-being along with their oral cavity is part of what we do daily. The American Academy of Periodontology’s statement regarding periodontal management of the pregnant patient states that:

1. Preventive oral care should be provided as early in pregnancy as possible;
2. Women should be encouraged to achieve a high level of oral hygiene prior to becoming pregnant and throughout their pregnancies;
3. If an oral examination indicates a need for periodontal scaling and root planing, these procedures should be scheduled early in the second trimester;
4. The presence of an acute infection, abscess, or other potentially disseminating sources of sepsis may warrant prompt intervention irrespective of the stage of pregnancy;
5. Diagnosis and treatment considerations should include diagnosis and evaluation of the patient’s periodontal condition and medical status;
6. The dental professional should educate the patient on the possible implications of periodontitis on pregnancy outcomes;
7. Consult the patient’s health care provider with an emphasis on the gestational age of the fetus; and
8. Proper periodontal examination and treatment, if indicated, may be beneficial for the mother’s pregnancy outcome.¹⁹

The American College of Obstetricians and Gynecologists, the March of Dimes, the National Nursing Association, and others have approved the content of these treatment recommendations. Currently the obstetric community does not have an official statement on dental treatment for the pregnant patient. However, as more information is discovered about periodontitis and its effects on pregnancy outcomes, an official statement may be forthcoming. With such a statement, obstetricians could formalize support for patients receiving dental treatment during pregnancy.

REFERENCES

1. Protecting Oral Health Throughout Your Life. American Academy of Periodontology. Available at: www.perio.org/consumer/women.htm. Accessed September 20, 2005.
2. National Center for Health Statistics. Final Natality Data. Available at: www.marchofdimes.com/peristats. Accessed September 20, 2005.
3. Williams CE, Davenport ES, Sterne JA, Sivapathasundaram V, Fearne JM, Curtis MA. Mechanisms of risk in preterm low-birthweight infants. Periodontol 2000 . 2000;23:142-150.
4. Healthy People 2000 Final Review. Division of Health Promotion Statistics. National Center for Health Statistics. Available at: www.cdc.gov/nchs/data/hp2000/hp2k01.pdf. Accessed November 16, 2005.
5. Offenbacher S, Katz V, Fertik G. Periodontal infection as a possible risk factor for preterm low birth weight. J Periodontol. 1996;67:1103-1113.
6. Offenbacher S, Jared HL, O’Reilly PG. Potential pathogenic mechanisms of periodontitis associated pregnancy complications. Ann Periodontol. 1998;3:233-250.
7. Davenport ES, Williams CE, Sterne JA, Murad S, Sivapathasundram V, Curtis MA. Maternal periodontal disease and preterm low birthweight: case-control study. J Dent Res. 2002;81:313-318.
8. Jeffcoat MK, Geurs NC, Reddy MS, Cliver SP, Goldenberg RL, Hauth JC. Periodontal infection and preterm birth: results of a prospective study. J Am Dent Assoc. 2001;132:875-880.
9. Lunardelli AN, Peres MA. Is there an association between periodontal disease, prematurity and low birth weight? A population-based study. J Clin Periodontol. 2005;32:938-946.
10. Noack B, Klingenberg J, Weigelt J, Hoffman T. Periodontal status and preterm low birth weight: a case control study. J Periodontal Res. 2005;40:339-345.
11. Radnai M, Gorzo I, Nage E, Urban E, Novak T, Pal A. A possible association between preterm birth and early periodontitis. A pilot study. J Clin Periodontol. 2004;31:736-741.
12. Dortbudak O, Eberhardt R, Ulm M, Persson GR. Periodontitis, A marker of risk in pregnancy for preterm birth. J Clin Periodontol. 2005;32:45-52.
13. Jarjoura K, Devine PC, Perez-Delboy A, Herrera-Abreu M, D’Alton M, Papapanou PN. Markers of periodontal infection and preterm birth. Amer J Obstet Gynecol. 2005;192:513-519.
14. Moss KL, Beck JD, Offenbacher S. Clinical risk factors associated with incidence and progression of periodontal conditions in pregnant women. J Clin Periodontol. 2005;32:492-498.
15. Lopez NJ, Smith PC, Gutierrez J. Higher risk of preterm birth and low birth weight in women with periodontal disease. J Dent Res. 2002;81:58-63.
16. Lopez N, Smith PC, Gutierrez J. Periodontal therapy may reduce the risk of preterm low birth weight in women with periodontal disease: A randomized clinical trial. J Periodontol. 2002;73:911-924.
17. Jeffcoat MK, Hauth JC, Geurs NC, et al. Periodontal disease and preterm birth: results of a pilot intervention study. J Periodontol. 2003;74:1214-1218.
18. MOTOR: Maternal Oral Therapy to Reduce Obstetric Risk. Available at www.clinicaltrials.gov/ct/show/NCT00097656?order=1. Accessed November 16, 2005.
19. Task Force on Periodontal Treatment of Pregnant Women, American Academy of Periodontology. American Academy of Periodontology statement regarding periodontal management of the pregnant patient. J Periodontol. 2004;75:495.

From Dimensions of Dental Hygiene. Nov 2005;3(11):14, 16, 18.