History of Periodontal Treatment and Risk for Intrauterine Growth Restriction (IUGR)

Cande V. Ananth; Howard F. Andrews; Panos N. Papapanou; Angela M. Ward; Emilie Bruzelius; Mary Lee Conicella; David A. Albert


BMC Oral Health. 2018;18(161) 

In This Article


Of the 32,168 women in the study, 18,593 (57.8%) received some form of dental treatment during the study period; 9.0% (n = 2895) received periodontal treatment, 41.2% (n = 13,246) received prophylaxis and 7.6% (n = 2452) received some other form of dental treatment (Table 1). The mean maternal age at the time of delivery was 30.8 (standard deviation (SD) = 5.6); subjects lived in zip codes with median Black population of 5% (range 0–99), and median Hispanic population of 8% (range 0–100). Complications of pregnancy were documented for 33.9% of the women in the study. On average, women were enrolled in a dental plan for 27.9 months (SD = 13.3) during the study period. There were relatively small differences between dental treatment groups with respect to each of the above covariates.

Table 2 shows the frequency of each type of periodontal treatment in the cohort. The most frequent non-surgical periodontal procedure was scaling and root planing, which was documented for 7.4% (n = 2388) of the women. Full mouth debridement (n = 584, 1.8%) and localized delivery of chemotherapeutic agents (n = 229, 0.7%) were less frequent. Surgical periodontal procedures occurred only rarely. For over two thirds of the 2895 women who received periodontal treatment during the study period, that treatment occurred only in the period after birth (n = 1956, 67.6%). A total of 440 (15.2%) received dental treatment only during gestation, and 343 (11.8%) received treatment in the period prior to conception. 753 (2.6%) received treatment in the gestation and post-gestation periods, 550 (1.9%) received treatment in the pre-gestation and post-gestation periods, and 232 (0.8%) received treatment in the pre-gestation and gestation periods.

IUGR was documented in 2027 fetuses (6.3%). The association between dental treatment before, during and after gestation and the risk of IUGR is shown in Table 3. The incidence of IUGR was 9.2% (n = 192) among those receiving periodontal treatment after delivery and 6.1% (n = 1835) for those receiving no periodontal treatment. The odds of IUGR for those receiving periodontal treatment post-gestation compared to those receiving no periodontal treatment was 1.5 (95% CI 1.2, 1.8) following adjustment for confounders. The odds of IUGR was elevated among multiparous women who received periodontal treatment post-gestation (OR 1.6, 95% CI 1.3, 1.9). Among primiparous women who received periodontal treatment post-gestation, the risk of IUGR was not elevated (OR 1.3, 95% CI 1.0, 1.8).

The rate of IUGR among those with no dental treatment at any time before, during or after pregnancy was 6.0%, which was marginally but significantly lower than the IUGR rate of those who received any treatment (6.5%; p = 0.048); there was also a marginally significant difference in IUGR rates in the post-gestational period between those who received no dental treatment in this period (6.1%) and those who received some form of dental treatment in this period (6.6%; p = .049). The slightly elevated IUGR rates of those receiving any form of dental treatment is clearly driven by the increased IUGR rates associated with periodontal treatment, as shown in Table 3.

Sensitivity Analysis for Unmeasured Confounding

The odds ratios corrected for unmeasured confounder(s) are shown in Figure 1. For instance, if the odds ratio of IUGR comparing the presence versus absence of an unmeasured confounder was 2.0, the bias-corrected odds ratio for each of the three scenarios were 0.7 (95% CI 0.5, 1.1) for pre-gestation periodontal treatment, 1.2 (95% CI 0.9, 1.8) for periodontal treatment during pregnancy, and 1.5 (95% CI 1.3, 1.8) for periodontal treatment post-gestation. For odds ratios of the unmeasured confounder over 5, the bias-corrected odds ratio were enhanced for both periodontal treatment during pregnancy and post-gestation. These findings confirm the confounder-adjusted odds ratios reported earlier (Table 3), and when unmeasured confounding is taken into account, the associations between periodontal treatment both during pregnancy and post-gestation are associated with increased odds of IUGR.

Figure 1.

Sensitivity Analysis for Unmeasured Confounding Between Periodontal Treatment Before, During and Post-Gestation and IUGR. Sensitivity analysis to evaluate the impact of unmeasured confounding of the association between periodontal treatment before (top panel), during (middle panel), and post-gestation (bottom panel) and IUGR. The observed confounder-adjusted odds ratio and 95% confidence interval are also shown for each panel. The unmeasured confounding bias-corrected odds ratio of IUGR for each of the three periodontal treatment periods are shown for prevalence estimates varying from 0.5 to 6.0% of the unmeasured confounder among both the IUGR and non-IUGR groups. The odds ratio of IUGR in relation to the unmeasured confounder is assumed to be 1.25. The red circle for each panel shows the bias-corrected odds ratio for one scenario of the prevalence of the unmeasured confounder of 2% and 4% among IUGR and non-IUGR groups, respectively, and the odds ratio of IUGR in relation to the unmeasured confounder of 1.25. The bias-corrected odds ratio for each of the three scenarios are 0.9 (95% CI 0.6, 1.5) for pre-gestation periodontal treatment, 1.6 (95% CI 1.1, 2.3) for periodontal treatment during pregnancy, and 2.0 (95% CI 1.6, 2.3) for periodontal treatment post-gestation

To determine whether severity of post-gestation periodontal care was associated with the likelihood of IUGR, we developed a four-category measure capturing the number of claims for post-gestational maternal periodontal care: zero, one, two, and three or more. The rate of IUGR increased from 6.1% for those with no periodontal care to 8.1% among those with 1 instance of periodontal treatment, 9.8% for those with 2 instances of periodontal treatment, and peaking at 11.1% for those with 3 or more instances of periodontal treatment after birth (P < 0.01).