The Association of Maternal Periodontal Disease with Preterm Delivery: A Prospective Study

Abstract

Introduction: The association of maternal periodontitis with Preterm Birth (PB) and low birth weight (LBW), which has been suggested by a number of retrospective studies, was examined by a prospective follow-up study.

Methods: A total of 215 pregnant women from Hartford Hospital, Connecticutwere offered a dental screening during a routine prenatal care visit. Patients were given a score of 1-4 indicating their overall oral health status. A score of 1 indicated no oral care needed (assigned to group A). A score of 2 and 3 signified the need for routine prophylaxis with radiographic imaging and the need for comprehensive care, respectively (assigned to group B). A score of 4 indicated a need for urgent treatment (assigned to group C). All patients were treated as indicated and prospectively followed to delivery over a 12-month rolling recruitment.

Results: Of the 215 women, 25 (12%) had a preterm birth, including 15 (9%) from group B (n=165), and 10 (22%) from group C (n=45). There were significant associations between severity of periodontal disease and probabilities of PB (<37 weeks, <34 weeks, and <32 weeks). Adjusted odds ratios (95% CI) for the above PB parameters are 2.46 (1.01– 6.01), 3.69 (1.01– 13.47), 16.07 (1.76 – 147.04), respectively. However, no association was found between severity of periodontal disease and LBW at term (<2500g) or small for gestational age.

Conclusions: Our data suggests that maternal periodontal disease may significantly increase the risk of preterm birth, even though routine dental prophylaxis and / or treatment have been given during pregnancy.

Keywords: Preterm delivery; Dental care; Periodontitis; High risk pregnancy

Introduction

Despite many advances in maternal and fetal care during pregnancy, preterm birth remains a significant cause of neonatal morbidity and mortality. It is estimated that 15 million babies per year are born before 37 weeks gestation with 1 million deaths each year secondary to preterm birth complications [1]. While some causes of preterm birth can be prevented with routine prenatal care, many causes are still undiscovered or uncertain.

In 1996, maternal periodontal disease was first proposed as one of the risk factors for preterm birth and low birth weight [2]. Since then, a number of studies have investigated the potential relationship between periodontitis and preterm birth and low birth weight [3-5]. However, the majority of studies were retrospective and the results have been controversial. Hence, nearly 20 years later, prospective studies with a greater degree of standardization are still needed in order to confirm this association.

The presence of gingival inflammation is commonly used for periodontal disease diagnosis. While some measurements used in periodontal disease diagnosis can be affected by the pregnant state, many studies have shown that pregnancy does not cause gingivitis and its presence in pregnancy would therefore be indicative of poor oral health at the onset of pregnancy [6]. Probing depth is also a commonly used measurement for periodontal disease and often used as an indicator for disease advancement [7]. Although there is no standard definition for periodontal disease, we believe the measurement of gingival inflammation and probing depth more accurately identify pregnant patients with periodontal disease.

The objective of this study is to observe whether there is an association between poor oral health and adverse pregnancy outcome by prospectively following pregnant women over a 12 month rolling recruitment.

Methods

This study was conducted in the high-risk Obstetrics clinic of Women’s Ambulatory Health Services (WAHS) at Hartford Hospital. A total of 215 high risk pregnant patients were offered a dental screening during a routine prenatal care visit. All patients included in the study will have at least one risk factor to be considered a high-risk pregnancy. Although standard of care is for an annual dental prophylaxis, many of these patients do not routinely have, or have not had, a dental exam. A database will be established to track maternal data and follow neonatal outcomes to determine the effect of appropriate dental care during pregnancy in this high-risk population. Because poor oral health has been linked to preterm labor and intra-uterine growth restriction (IUGR), risk factors for these conditions will be followed in patients agreeing to concurrent dental care.

At their prenatal visit, a dental hygienist screened the participating patients after the routine prenatal exam. Dental examination criteria included evidence of plaque (light/moderate/heavy); level of gingival inflammation (mild/moderate/severe); localized versus diffuse inflammation; periodontal health readings of probing depth (=3mm/ 4-5mm/ 6-8mm/ >9mm); calculus evidence (light/moderate/heavy); and amount of tooth staining (light/moderate/heavy). The primary reason for examination findings was also noted, including poor oral hygiene, food/beverage, or tobacco habit (Form 1).

Based on the dental exam findings, patients were given a score of 1-4 indicating their overall oral health status. A score of 1 indicated no current oral health needs and up-to-date oral screening. A score of 2 signified the need for routine prophylaxis and radiographic imaging. A score of 3 indicated a need for comprehensive care. A score of 4 indicated a need for urgent treatment due to pain. Patients with a score of 1 were assigned to study group A. Patients with a score of 2 or 3 were assigned to study group B. Patients with a score of 4 were assigned to study group C.

Patients included in the study also received a thorough obstetrical and gynecological interview to identify potential confounding factors of preterm delivery. Obstetrical risk factors for PTD including history of PTD, history of Preterm Premature Rupture Of Membranes (PPROM), IUGR, history of drug abuse, and history of alcohol or tobacco use were recorded (Form 2).

Patients requiring treatment for periodontal disease were offered treatment options along with dental education. Those patients needingor desiring routine prophylaxis and scaling were given treatment, and those requiring further treatment were either given a follow-up appointment or referred to their own dentist. Followup appointments were scheduled as needed to evaluate need for retreatment and to follow up on each patient’s dental hygiene. Patients requiring dental radiography were told to follow up with their dentist postpartum. Patient oral health was followed throughout their prenatal care, but baseline screening served as the ultimate basis for risk-level stratification.

Study patients were then followed to delivery, and the birth outcomes of the three study groups such as APGAR scores at 1 and 5 minutes were recorded. Deliveries were recorded as full-term (=37 weeks gestation) or pre-term (<37 weeks gestation). Any complication of preterm labor and treatment received was also noted. Neonatal birth weights were recorded as normal (=2500g) or low (<2500g). The gender of the babies is not available for this study, hence the gender specific criteria for female infants were used, which is less than the tenth percentile for each specific gestational age. Chi-square tests were used to determine differences in proportions of the outcomes between the three maternal dental risk groups. Logistic regressions were used to estimate odds ratio of preterm delivery outcomes (<37 wks, <34 wks, <32 wks) based on oral hygiene (A vs. B&C) along with other risk factors, while adjusting for confounding factors (i.e. history of PTD, age, smoking, PPROM, ETOH, and drug use).</p>

Results

Our data suggests that there is a significant association between the severity of periodontal disease and the probabilities of moderately preterm birth (<37 weeks), very preterm birth (<34 weeks), and extremely preterm birth (<3432 weeks). Adjusted odds ratios and 95% CI’s are 2.46 (1.01– 6.01), 3.69 (1.01– 13.47), 16.07 (1.76– 147.04), respectively (Figure 1). There was no significant association between the severity of periodontal disease and the probability of low birth weight at term (<342500g). There also was no significant association between the severity of periodontal disease and the probability of SGA (small for gestational age). Maternal age was negatively associated with an odds of SGA (Adjusted OR = 0.842, 95% CL=0.748 – 0.948). There was no significant association between the severity of periodontal disease and APGAR scores at either 1 minute or 5 minutes.

    

    

    Figure 1:  The figure shows the adjusted odds ratios for Pre-Term Delivery
(PTD) in those with poor dental hygiene, groups B or C compared to group A.