Observational studyVaccine2023
Tdap vaccination during pregnancy and risk of chorioamnionitis and related infant outcomes.
Observational study in Vaccine, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
6 citing papers in PubMed, 11 citations in OpenAlex.
- Vaccinations During Pregnancy Protect the Mother-Infant Dyad and Are Generally Safe.Acta paediatrica (Oslo, Norway : 1992) · 2026Review
- The Effect of Maternal Pertussis Vaccination on Neonatal Health Outcomes in the Dutch Pregnancy Drug Register.Birth defects research · 2026Article
- Post-marketing safety surveillance of tetanus, diphtheria, and acellular pertussis (Tdap) vaccine: a disproportionality analysis of the vaccine adverse event reporting system (2015-2025).Frontiers in cellular and infection microbiology · 2026Article
- Research progress in vaccination during pregnancy.Frontiers in immunology · 2025Review
- Prenatal Maternal Immunization for Infant Protection: A Review of the Vaccines Recommended, Infant Immunity and Future Research Directions.Pathogens (Basel, Switzerland) · 2024Review
- Safety and Clinical Benefits of AdacelInfectious diseases and therapy · 2023Review
Corrections and comments
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Authors and funding
13 authors at 8 institutions in 1 country.
Funding
Abstract
introductionAn increased risk of chorioamnionitis in people receiving tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during pregnancy has been reported. The importance of this association is unclear as additional study has not demonstrated increased adverse infant outcomes associated with Tdap vaccination in pregnancy.
methodsWe conducted a retrospective observational cohort study of pregnant people ages 15-49 years with singleton pregnancies ending in live birth who were members of 8 Vaccine Safety Datalink (VSD) sites during October 2016-September 2018. We used a time-dependent covariate Cox model with stabilized inverse probability weights applied to evaluate associations between Tdap vaccination during pregnancy and chorioamnionitis and preterm birth outcomes. We used Poisson regression with robust variance with stabilized inverse probability weights applied to evaluate the association of Tdap vaccination with adverse infant outcomes. We performed medical record reviews on a random sample of patients with ICD-10-CM-diagnosed chorioamnionitis to determine positive predictive values (PPV) of coded chorioamnionitisfor "probable clinical chorioamnionitis," "possible clinical chorioamnionitis," or "histologic chorioamnionitis."
resultsWe included 118,211 pregnant people; 103,258 (87%) received Tdap vaccine during pregnancy; 8098 (7%) were diagnosed with chorioamnionitis. The adjusted hazard ratio for chorioamnionitis in the Tdap vaccine-exposed group compared to unexposed was 0.96 (95% CI 0.90-1.03). There was no association between Tdap vaccine and preterm birth or adverse infant outcomes associated with chorioamnionitis. Chart reviews were performed for 528 pregnant people with chorioamnionitis. The PPV for clinical (probable or possible clinical chorioamnionitis) was 48% and 59% for histologic chorioamnionitis. The PPV for the combined outcome of clinical or histologic chorioamnionitis was 81%. CONCLUSIONS AND RELEVANCE: Tdap vaccine exposure during pregnancy was not associated with chorioamnionitis, preterm birth, or adverse infant outcomes. ICD-10 codes for chorioamnionitis lack specificity for clinical chorioamnionitis and should be a recognized limitation when interpreting results.
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