Maternal periodontitis and preterm delivery: hospital based study

Abstract:

Background:

To find out the association between preterm delivery and maternal periodontitis among pregnant women visiting a tertiary teaching hospital located in eastern Nepal this study was planned.

Materials and method:

Those women who underwent spontaneous vaginal preterm delivery of less than 37 weeks of gestation were cases group and women who undergo vaginal delivery at term of equal or more of 37 weeks of gestation on the same day of preterm delivery were considered as control group. Estimation of gestational age was based on the last menstrual period which was recorded in the patient`s medical record.

Result: The result of this study showed that for preterm delivery periodontal disease is an independent risk factor. Extention of disease, increased probing depths have been associated with a higher risk for progression of periodontal disease.

Conclusion: this study will be beneficial to those women with periodontal disease who have higher changes of preterm delivery for early detection and for making treatment planning.

The promotion of the early detection and treatment of periodontal disease in women before and during pregnancy will be beneficial especially for women at risk for preterm delivery.

Kewords – preterm delivery, periodontitis, plaque index , gingival index , clinical attachment loss

INTRODUCTION

Periodontitis is defined as “ an inflammatory disease of the supporting tissues of the teeth caused by specific microorganisms or group of micro-organisms resulting in progressive destruction of periodontal ligament and alveolar bone with pocket formation, recession or both”. According to the WHO, a preterm birth is a birth, regardless of birth weight which occurs up to 37 menstrual weeks of gestation. The clinical importance of the time of onset of the last menstrual period is for determining fetal age because it is usually known and when spontaneous and regular in past, it most often is followed by ovulation and fertilization after 2 weeks. 2, 3 For 30%–50% of all cases infections are major causes for preterm deliveries according to some investigators. 4 Other infectious processes occurring elsewhere in the body may contribute to preterm delivery. One such infection may be periodontal disease. 5 Major determinant of neonatal morbidity and mortality is preterm delivery. 6 Preterm birth also has long-term consequences for neonant which includes an increased risk of neurological impairments and behavior disorders and higher rates of chronic health disorders as compare to the children born at term. 5 The recent evidences suggest that specific microorganisms or groups of species which include Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythea and Treponema denticola occur more frequently and also in higher levels and proportions in periodontitis sites.

Material and method

Population and sample

The study populations were patients getting admitted in the department of Obstetrics and Gynecology who fulfilled the inclusion criteria. Only those patients who were willing to participate were included for the examination.

Those women who underwent spontaneous vaginal preterm delivery of less than 37 weeks of gestation) were cases group and women who undergo vaginal delivery at term of equal or more of 37 weeks of gestation on the same day of preterm delivery were considered as control group. Estimation of gestational age was based on the last menstrual period, which was in medical record of patient. Patients with irregular cycle or not sure of date and also not having early trimester scan were excluded from the study. Periodontal examinations were performed at the maternity ward.

The periodontal examinations included dental plaque, gingival condition, clinical attachment loss and probing pocket depth.

The Plaque index was taken for recording the presence of plaque. The gingival index was used for recording gingival condition. The third molar were not examined or scored in the upper or lower arch. The examination for plaque index was preceded the examination for the gingival index.

The clinical periodontal examinations were carried out manually by using UNC-15 probe (Hu-Friedy, IL, USA). The CAL and PD were measured in 4 sites (mesial-facial, mid-facial, distal-facial and palatal/lingual) per tooth. All the clinical data were collected by a single investigator. After clinical examination, the patients were given self-reporting questionnaires to collect the data regarding socioeconomographic and personal history.

The instrument used were Plane mouth mirror, UNC-15 probe, Explorer, Tweezer, Kidney tray, Gauze and cotton, Gloves and mouth mask, Disinfectant solution for hand washing – Betadine 5. 5 % Cloth hand towel.

Ethical clearance

It was obtained from institutional ethical review board prior to start of this investigation. Written consent was taken from patient.

Statistical Analysis

Evaluation of the existence of an association between periodontal disease and preterm delivery was obtained by means of a multivariate logistic regression model also considering other risk factors for preterm delivery.

Collected data was entered in Microsoft excel 2007 and converted it into Statistical package for social science (SPSS) version 11. 5 for statistical analysis.

Descriptive statistics was calculated by mean, percentage and proportion and tabular. graphical presentation was done.

For inferential statistics Chi square test, odd ratio, independent t-test were applied to find out significance between case and control and other variables at 95% CI where p= 0. 05. p-value less than 0. 05 were considered statistically significant.

Results

The age of population ranged from 18 to 43 with mean age 22. 34 ±4. 158.

Maximum numbers of population were 20-34 age group whereas minimum numbers were more than 34 age group. Results of different parameters which were taken are as follow in Table 2a, 2b, 2c, 2d, 2e.

Summary of results showing association or non-association between different parameters which were taken are shown in Table 3.

Discussion

Potential link between periodontal disease and pregnancy outcomes have been investigated for many years.

In 1996 Offenbacher et al published the first clinical investigation into links between pregnancy outcome and periodontitis in human. 8

Our study found statistically association between maternal periodontitis and preterm delivery (CAL p= 0. 021) which was statistically significant and thus the hypothesis that for undesirable pregnancy outcomes periodontal disease is not a risk factor was rejected.

Age group between 20-34 years is suggested to be the most appropriate age for giving birth to children. 9 In our study mean age of mothers were 22. 34 ± 4. 158 years which falls within this range of fertile age.

Mothers belonging to different religion group have been included in the study(Table 2). 80% of the mothers were Hindus, 6% Buddhist, 5% Kirant, 4% Christian, 5% Muslim Among them, Muslim and Kirant population showed more prevalence of preterm delivery which indicate that ethnicity play a role in preterm delivery similar to the studies by Horton et al 10 and Offenbacher et al. 11 However in contrasts to our study Bassani et al12 and Mitchell-Lewis et al13 had shown different results.

The type of diet was not significant among the group where 95% were non-vegetarian and 5% were vegetarian (Table 3).

In our study, parity was not significant for preterm delivery(Table 3) similar to study done by Alexis Shub et al14 who found there is no difference between the controls and cases group with respect to difference between marital status, parity and age. 15 However, similar to our study there are many studies which have shown parity as a significant risk factor for preterm delivery like Mumghamba et al. 16

For both periodontitis and adverse outcomes of pregnancy smoking is considered as one of the principal risk factor. 17, 18 The rate of smoking among pregnant women fluctuates between 10 % and 20%. 19, 20 In our study 4% of the total population smoked cigarette. Among cases 5% were smokers and 3% were smokers among controls.

Our study showed no significant association of smoking with preterm delivery (Table 3) which is as similar to the research done by Bosnjak et al. 21However, this study is in contrast to the study done by various researchers20, 22, 23 who showed significant relation between preterm delivery and smoking.

The difference in result may be due to lack of sufficient definition criteria for smoking habits and severity, for example the number of cigarettes per day and period of smoking like during or prior to pregnancy. 24

Since passive smoking has role in adverse pregnancy outcome participants were assessed for it. Based on the self-reported answer it was found that 23% of the husband of case group smoked and the pregnant mothers were exposed to passive smoking. Our study showed significant relationship of passive smoking in pregnancy outcome (Table 2) which is similar to the study done by Rajapakse et al 24 but in contrast to this study no association has been seen in the study by Toygar et al. 25

The insignificant association of smoking to preterm delivery found in our study was may be due to hesitation to report self-smoking since it was questionnaire based study (Table 3).

Regarding prenatal care, no significant association with preterm delivery was found in our study (Table 3) which is similar to study done by Basanjak et al. 22 The level of prenatal care among the groups of mothers giving birth to full term normal weight infants and mothers giving birth to preterm low birth weight infants was similar. In contrast to our study, various authors have shown that mothers delivering low birth weight infants or preterm low-birth weight infants has been provided insufficient prenatal care. 25, 26 Lunardelli AN and Peres MA22 also showed association between prematurity and fewer prenatal consultations. Likewise, in a study conducted by Vettore MV et al27 showed that periodontal disease was the risk factor for low birth weight but inadequate prenatal care showed association with adverse birth outcome which was significant.

No significant difference was obtain regarding prenatal care like visiting to a dentist last year, taking advice from health professional (Table 2). This finding of ours was similar to the findings reported by Offenbacher et al. 28 Majority of Nepalese population still lack of basic facility like toilet which is related to the socio economic status. 17. 5% population showed lack of toilet facility, 62% population utilized firewood as the cooking fuel.

Regarding alcohol use no significant association with preterm delivery has been found in our study (Table 2) which is similar to the study done by Bassaniet al. 13

In our study, no difference in the level of tobacco use among case group and control group mothers was seen (Table 3) which is similar to the study done by Offenbacher et al28 who showed no difference in the level of tobacco use among preterm low birth weight group and normal birth weight group mothers. However, in contrast to these studies, Goldenberg et al26 2008 and Bosnjak et al22 found significant association between preterm birth infants and normal birth weight infants.

Previous history of preterm delivery, low birth weight baby and previous abortion were not associated with preterm delivery in our study (Table 2). The results of our study are in difference to the study done by Baskaradoss10Augeda et at27 and Davenport et al29 who found significant association between them.

For preterm delivery physical exertion during pregnancy is an important risk factor. Based on the workload, hours of work per day and carrying heavy load analysis was made. Significant association has been found in this study (Table 2) similar to the study done by Baskaradoss. 22 In contrast to this study Pompiiet al30 did not find any kind of association between the two.

Stress has been also associated with pre-term birth of infants. There may be different kind of stress like violence, financial situation, family problems, problems at work place. 27 Similar to these findings, stress was found significantly associated with preterm birth in our study (Table 2) which is in agreement with the study done by Noack et al31, Pompeii et al30 and Eskenazi et al32

This is explained on the basis that stress stimulate pituitary gland which release cortisol hormone. Cortisol enters into saliva and cause reduction of inflammatory cells inhibiting the immune response and thus causing the periodontitis.

Elevated percentages of pregnant women with no education or only primary education are frequently associated with PTB and/or LBW34, 25, 27 and periodontitis. 30 Education in relation to preterm delivery was found highly significant in our study (Table 2) which is similar to the studies done by Sequeria et al24 and Toygar et al. Mother with no education or primary education or middle school level education has higher chances for preterm delivery in our study(table 3). On the contrary, an insignificant difference (P> 0. 05) between preterm delivery and maternal periodontitis was found in the study by Davenport et al.

In the present study, socioeconomic status was scored based on scoring criteria which included education, occupation and family income according to the scale given by Kuppuswamy. Various studies revealed that lower socioeconomic status group had higher chances of giving birth to low birth weight child. The result of our study showed significant association between low birth weight children and different socioeconomic status of mothers(Table 2), which is in agreement with study done by Lunardelli et al. 20 However, in contrast to this study the level of socioeconomic status failed to show any significant difference among the two groups of mother in studies done by Moore S et al35 and Noack et al.

Majority of our population were from medium socioeconomic class with low education level similar to the studies done by Rajapakseet.

Our study showed that 84% of subjects brushed their teeth once a day and rest brushed twice in a day. Among case group, 95% gave history of brushing the teeth once a day and 5% brushing teeth twice in a day. Among them 19. 5% gave the history of bleeding while brushing.

Oral hygiene status was measured with the help of PI and gingival index GI. An efficient index system should be quick and easy to use with minimal instrumentation. It must be reproducible and must reflect accurately degrees of pathology.

Severity of periodontitis was measured with the help of PD and CAL (Table 1). Extent and severity of PD corresponds with periodontal disease progression and increased probing depths have been associated with a higher risk for periodontal disease progression44 the combination of PD and CAL identifies the subjects with true periodontal pockets. The rationale behind using PD and CAL in combination for measuring periodontal disease severity is that PD suggests the presence of active disease and CAL represents a cumulative measure of periodontal tissue destruction throughout life.

In our study chronic disease like diabetes mellitus, chronic hypertension was excluded. Diabetes mellitus is known to be associated with more severe periodontal disease and higher low birth weight. The exclusion of women with chronic hypertension avoided bias of confounding caused by the continuous use of anti-hypertensive medications, strongly related to periodontal status changes.

Despite apparent conflicting data, the majority of studies report that periodontal treatment is safe for pregnant women and improves periodontal status. The pregnant woman is a particular patient, so in order to decrease the impact of periodontal disease on preterm birth incidence, the early diagnosis and treatment of periodontal disease in them should be recommended. The preventive oral care is the best way to prevent oral diseases and their consequences on pregnancy.

Conclusion: The results of our study showed that periodontal disease is an independent risk factor for preterm delivery. Caution must be taken in interpreting the applicability of current data until these finding can be confirmed by larger, prospective studies.

Cooperation between obstetricians or general practitioners and periodontists should be developed.

The promotion of the early detection and treatment of periodontal disease in women before and during pregnancy will be beneficial especially for women at risk for preterm delivery.