S Bala, S Narula Sr., K Sangwan, R Sharma, R Shyam
periodontitis, pregnancy, preterm low birth weight
S Bala, S Narula Sr., K Sangwan, R Sharma, R Shyam. Effect of Periodontitis and Role of Periodontal Therapy in Pregnancy Outcome. The Internet Journal of Dental Science. 2010 Volume 10 Number 1.
For many years Periodontitis has been considered an infectious disease confined to the oral cavity. However, a number of research reports, in the past one decade, have suggested that periodontal infection may play a significant role in the systemic health of humans. The influences of periodontal infection have been documented in relation to cardiovascular disease, diabetes, pulmonary disease and adverse pregnancy outcome i.e. preterm delivery and low birth weight1, 2.
Preterm delivery and low birth weight (PLBW) 3defined as delivery before 37 weeks of gestation and birth weight less than 2500 gm, are major public health problems in the world. Infant mortality and morbidity sharply increases as birth weight decreases4.
Many risk factors have been proposed for premature rupture of membrane and preterm labor, including infection and inflammation5. Various factors have been found responsible for PLBW. The traditional risk factors being the smoking, alcohol, drug abuse, inadequate prenatal care, genetics, low socioeconomic status, hypertension, diabetes, high or low maternal age and genitourinary tract infection. However these risk factors have not been found in approximately 25% of cases, leading to continued search for other causes6.
In India the incidence of preterm birth lies between 10-15% (ICMR 1990)7. Premature low birth accounts for more than 60% of infant mortality, not attributable to anatomic or chromosomal congenital defects8. The emotional, psychological and financial burden on families who experience PLBW babies can have profound and long term consequences on society9.
The present study was designed to assess the role of periodontal therapy in pregnancy outcome in northern part of India (Haryana).
Material & Methods
The present study was conducted in the Department of Periodontics Govt. Dental College Rohtak (Haryana) India, in collaboration with the Department of Obstetrics & Gynecology, Post Graduate Institute of Medical Sciences Rohtak (Haryana) India. Medical records of the patients were thoroughly examined to extract the relevant data, which was utilized to determine the eligibility for study. Study population consisted of healthy, primiparous women with singleton gestation, in their second trimester of pregnancy, having not less than 18 natural teeth and with the intention to deliver at hospital. After screening 976 primiparous women, 500 patients fulfilling the selection criteria were enrolled for the study. All enrolled subjects received a full mouth examination and data recorded included: Plaque index (PI), Gingival Index (GI), Probing Pocket Depth (PPD), Clinical attachment level (CAL) and Bleeding on probing (BOP). The presence of 4 or more teeth with one or more sites with PPD
Group 1 subjects were educated about periodontal disease and were instructed for plaque control measures. Routine oral prophylaxis was provided to them and their periodontal characteristics were recorded before 28 weeks of gestation. They were monitored every 4-6 weeks till delivery. Group 2 subjects received no treatment during pregnancy and their periodontal characteristics were recorded before 28 weeks of gestation. They were also monitored for any change in their periodontal status every 4-6 weeks till delivery. Group 3 subjects received treatment i.e. scaling and root planing and their periodontal characteristics were recorded at the time of entry into the study (2 nd Trimester of pregnancy) and after treatment, but before 28 weeks of gestation.
Treatment of Periodontitis group resulted in improved Clinical parameters comparable to that of healthy group. (Table I)
Mean Birth Weight of children born to mothers of treated group (Gp3) was comparable to that of Healthy (Gp1) and significant difference (F=10∙76, df=2, 434 at p < ∙01 level of significance) was found when the same was compared within the groups and between the groups (Table II, III, IV)
Values of plaque index, when compared between groups and within groups was found to be significantly different (F=419∙26, df=2, 434) at ∙05 degree of confidence interval. (Table V, VI)
While comparing the gingival index in all the three groups by applying ANOVA, it was found that the value differed significantly between groups and within groups (F=1209∙92, df=2, 434) at ∙05 degree of confidence interval. . (Table VII, VIII)
The mean number of surfaces showing pocket depth
Mean of the number of surfaces showing clinical attachment loss (CAL), compared by ANOVA followed by Post Hoc analysis by Duncan’s test were found to differ significantly (F=807∙73, df 2, 434).
Sites showing bleeding on probing differed significantly, when comparison was done in the groups and between the groups (F=856∙78, df=2, 434)
The critical ratios for PLBW between healthy and Periodontitis group came out to be significant at p
To validate the relationship between periodontal infection and adverse pregnancy outcome various types of studies/trials had been carried out throughout the world, which included experimental, epidemiological, biochemical, immunological, histological, microbiological and interventional. A review of case control studies found this association controversial10. The present study was an interventional trial in an attempt to see the influence of periodontal therapy on pregnancy outcome on the lines of earlier intervention studies11, 12, 13with a different methodology.
The method used in this study attempted to exclude several known risk factors for PLBW, like high or low maternal age13, maternal smoking14,15,history of pervious PLBW 16, 17 ,multiple gestation13, systemic diseases18,19,20 genitourinary tract infection21.
After receiving periodontal therapy the women in the treatment group showed periodontal parameters comparable with the periodontally healthy women. Participation in the study positively affected subjects’ oral hygiene practices. The potential strength of present study was the presence of “exposure variable” (periodontal status) prior to the onset of the “disease” (LBW) and was in active state, allowing for evaluation of the temporal sequence between exposure and disease of interest.
In this study mean birth weight of infants was compared in all the three groups and it was found that mothers who have been treated during pregnancy had babies with higher mean birth weight (2∙88 kg) as compared to mothers with periodontal disease who had a mean birth weight of 2.71 kg. This was found to be statistically significant. While mothers with healthy status had a mean birth weight (2.91kg) comparable to birth weight of infants, born to mothers in treatment group (2∙88 kg).
The prevalence of LBW is found to be around 15% in Asia22, while in India the incidence of pre-term labor lies between 10-15%7.The overall incidence in the present study was found to be 5∙42% which was in accordance with the earlier study by Lopez et al23 (6∙26%), and is quite low than the global range of 10-15%. This can be because of the exclusion of patients with well known risk factors for PLBW. When the incidence of PLBW was compared in different groups, it was found to be 3∙98% in healthy group (n=176), 4∙54% in treatment group (n=132) and 7∙75% in the Periodontitis group (n=129). When critical ratio of incidence was compared, statistically significant difference was found between group 1 and Group 2, CR being 6∙48 (P < 0∙05), between group 2 and group 3, CR being 4∙65 (P < 0∙05). While the difference was not significant when healthy and treated groups were compared (CR=0∙56).
Although results from our preliminary intervention study have suggested that the treatment for Periodontitis in pregnant mothers may reduce the risk of PLBW babies in the population studied, this study does not elucidate whether the association is causal in nature or not. However there are several lines of biochemical, immunological and histological evidences which support the hypothesis that periodontal disease is not a mere association, but is contributing to low birth weight.7, 24, 25, 26, 27 Thus the potential mechanisms that may explain the relationship between periodontal disease and PLBW bear comment.
As periodontal medicine is still in its infancy here in Asia, there is a compelling need to determine the possible association between adverse pregnancy outcome and periodontal infections. It is well documented that periodontal disease is a treatable and preventable condition. In the event of causal association of periodontal infection with PLBW, this will have potential applications in preventive oral health program as an integral component of prenatal care for pregnant mothers.
Within the limitations of the study (small sample size and study conducted at one center) it can be said that periodontal disease was associated with adverse pregnancy outcome. Periodontal therapy administered to the treatment group significantly changed the periodontal status and the same was comparable to that of the healthy group. This may be the reason for reduced number of preterm deliveries as well as improved birth weight in the treatment group as compared to the Periodontitis group.
The limited scope of this intervention study does not enable broad generalization regarding potential health care impact of these findings. Caution must be taken in interpreting the applicability of current data, till the findings are confirmed by large prospective multiple center investigations.