Periodontal treatment for preventing adverse pregnancy outcomes: a meta- and trial sequential analysis

Abstract

Objectives: Periodontal treatment might reduce adverse pregnancy outcomes. The efficacy of periodontal treatment to prevent preterm birth, low birth weight, and perinatal mortality was evaluated using meta-analysis and trial sequential analysis.

Methods: An existing systematic review was updated and meta-analyses performed. Risk of bias, heterogeneity, and publication bias were evaluated, and meta-regression performed. Subgroup analysis was used to compare different studies with low and high risk of bias and different populations, i.e., risk groups. Trial sequential analysis was used to assess risk of random errors.

Results: Thirteen randomized clinical trials evaluating 6283 pregnant women were meta-analyzed. Four and nine trials had low and high risk of bias, respectively. Overall, periodontal treatment had no significant effect on preterm birth (odds ratio [95% confidence interval] 0.79 [0.57-1.10]) or low birth weight (0.69 [0.43-1.13]). Trial sequential analysis demonstrated that futility was not reached for any of the outcomes. For populations with moderate occurrence (< 20%) of preterm birth or low birth weight, periodontal treatment was not efficacious for any of the outcomes, and trial sequential analyses indicated that further trials might be futile. For populations with high occurrence (≥ 20%) of preterm birth and low birth weight, periodontal treatment seemed to reduce the risk of preterm birth (0.42 [0.24-0.73]) and low birth weight (0.32 [0.15-0.67]), but trial sequential analyses showed that firm evidence was not reached. Periodontal treatment did not significantly affect perinatal mortality, and firm evidence was not reached. Risk of bias, but not publication bias or patients' age modified the effect estimates.

Conclusions: Providing periodontal treatment to pregnant women could potentially reduce the risks of perinatal outcomes, especially in mothers with high risks. Conclusive evidence could not be reached due to risks of bias, risks of random errors, and unclear effects of confounding. Further randomized clinical trials are required.

Fig 1. Periodontal treatment and preterm birth (PTB).

(A) Conventional meta-analyses were performed to analyze the effect of periodontal treatment in control populations with moderate (<20%) and high occurrence (≥20%) of PTB as well as in the total population. Heterogeneity was assessed using χ²-test and I²-statistics. (B) Trial sequential analysis of trials in population with moderate occurrence of PTB. The cumulative Z-score (black), i.e., the accumulated level of significance, was plotted against the number of participants accrued so far, which was compared with the heterogeneity-adjusted required information size (HRIS). Based on HRIS, the trial sequential monitoring boundary (TSMB) for benefit was plotted (grey oblique). The Z-curve nearly crosses the futility boundary, and HRIS is not reached. (C) Trial sequential analysis of trials in population with high occurrence of PTB. The Z-curve does not reach the HRIS, and does not cross the TSMB.

Fig 2. Periodontal treatment and low birth weight (LBW).

(A) Conventional meta-analyses were conducted to analyze the effect of periodontal treatment for populations with moderate (<20%) and high occurrence (≥20%) of LBW as well as in the total population. (B) Trial sequential analysis of trials in population with moderate occurrence of LBW. The Z-curve only initially crosses the conventional boundary, with trial sequential monitoring boundary (TSMB) for benefit and HRIS not being in reach. (C) Trial sequential analysis of trials in population with high occurrence of LBW. The Z-curve does not reach the HRIS, and does not cross the TSMB.

Fig 3. Periodontal treatment and perinatal mortality (PNM).

(A) Conventional meta-analyses were conducted to analyze the effect of periodontal treatment for populations with moderate (<1%) and high occurrence (≥1%) of PNM as well as in the total population. (B) and (C) Trial sequential analyses of trials in populations with moderate and high occurrence of PNM, respectively. The conventional boundary, the trial sequential monitoring boundary (TSMB) for benefit, the TSMB for futility, and the HRIS are not reached.