Preconception Periodontitis and Risk of Spontaneous Abortion in a Prospective Cohort Study

Abstract

Few studies have evaluated the association between periodontitis and spontaneous abortion (SAB), and all had limitations. We used data from the Pregnancy Study Online (PRESTO), a prospective preconception cohort study of 3,444 pregnancy planners in the United States and Canada (2019-2022), to address this question. Participants provided self-reported data on periodontitis diagnosis, treatment, and symptoms of severity (i.e., loose teeth) via the enrollment questionnaire. SAB (pregnancy loss at <20 weeks' gestation) was assessed via bimonthly follow-up questionnaires. Participants contributed person-time from the date of a positive pregnancy test to the gestational week of SAB, loss to follow-up, or 20 weeks' gestation, whichever came first. We fitted Cox regression models with weeks of gestation as the time scale to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs), and we used inverse probability of treatment weighting to account for differential loss to follow-up. We used probabilistic quantitative bias analysis to estimate the magnitude and direction of the effect of exposure misclassification bias on results. In weighted multivariable models, we saw no appreciable association between preconception periodontitis diagnosis (HR = 0.97, 95% CI: 0.76, 1.23) or treatment (HR = 1.01, 95% CI: 0.79, 1.27) and SAB. A history of loose teeth was positively associated with SAB (HR = 1.38, 95% CI: 0.88, 2.14). Quantitative bias analysis indicated that our findings were biased towards the null but with considerable uncertainty in the bias-adjusted results.

Keywords: periodontitis; prospective studies; spontaneous abortion.

Figure 1

Directed acyclic graph depicting potential confounders and precision variables in the association between preconception periodontitis and risk of spontaneous abortion, Pregnancy Study Online (PRESTO), 2019–2022. Data on all covariates were self-reported, and all variables were assessed at enrollment except for age (assessed at conception) and Healthy Eating Index score (assessed on a supplemental questionnaire 10 days after enrollment). Race/ethnicity, a social construct, was included as a proxy for a variety of potential exposures, including the impact of racism on an institutional, interpersonal, and internalized level (48). The node “unknown inflammatory predisposition” depicts a hypothesized predisposition to inflammatory conditions that may be related to the exposure, the outcome, and certain covariates. PCOS, polycystic ovary syndrome; SES, socioeconomic status.