{
  "abstract": "Objective To estimate the association between maternal COVID-19 vaccination during pregnancy and adverse neonatal and maternal outcomes.Design Population-based retrospective cohort study using a hospitalisation database linked with other health administrative databases.Setting Province of Quebec, Canada, from 1 May 2021 to 30 June 2023.Participants All singleton pregnancies resulting in a live birth or stillbirth at ≥20 weeks of gestation, excluding those with a conception date <42 weeks before the end of the study period.Primary outcome measures We used robust Poisson regression models to estimate adjusted risk ratios (aRRs) for chorioamnionitis, postpartum haemorrhage, caesarean delivery, preterm birth, very preterm birth, small for gestational age (SGA), maternal and neonatal admission to intensive care unit (ICU, NICU) and severe neonatal morbidity. We used a Cox regression model with a time-varying exposure variable to estimate adjusted HRs (aHRs) for stillbirth. Propensity score weighting was used to adjust for potential confounding.Results Among 140 073 singleton pregnancies resulting in live birth or stillbirth, 61 282 individuals (43.8%) received at least one dose of messenger RNA COVID-19 vaccine during pregnancy. Vaccination during pregnancy was not associated with an increased risk of chorioamnionitis (aRR 0.99, 95% CI 0.95 to 1.04), postpartum haemorrhage (aRR 1.03, 95% CI 0.99 to 1.06), very preterm birth (aRR 1.04, 95% CI 0.89 to 1.21) and stillbirth (aHR 1.14, 95% CI 0.94 to 1.39). Vaccination during pregnancy was significantly associated with a reduced risk of caesarean delivery (aRR 0.94, 95% CI 0.92 to 0.96), maternal ICU admission (aRR 0.80, 95% CI 0.65 to 0.98), SGA (aRR 0.94, 95% CI 0.91 to 0.98), NICU admission (aRR 0.91, 95% CI 0.85 to 0.96), preterm birth (aRR 0.94, 95% CI 0.90 to 0.99) and severe neonatal morbidity (aRR 0.91, 95% CI 0.85 to 0.98).Conclusions Our findings suggest that COVID-19 vaccination during pregnancy was not associated with an increased risk of adverse outcomes. Ongoing surveillance of the safety of maternal COVID-19 vaccination is essential as doses continue to be recommended for this group.",
  "authors": [
    {
      "affiliations": [
        "Médecine sociale et préventive, Université Laval Faculté de Médecine, Québec City, Quebec, Canada",
        "Centre de recherche du CHU de Québec-Université Laval Site CHUL, Québec City, Quebec, Canada"
      ],
      "name": "Marilou Kiely"
    },
    {
      "affiliations": [
        "Institut national de santé publique du Québec, Québec City, Quebec, Canada"
      ],
      "name": "Ella Diendere"
    },
    {
      "affiliations": [
        "Quebec National Institute of Public Health, Quebec City, Quebec, Canada"
      ],
      "name": "Isaora Dialahy"
    },
    {
      "affiliations": [
        "Institut national de santé publique du Québec, Québec City, Quebec, Canada"
      ],
      "name": "Gentiane Perrault-Sullivan"
    },
    {
      "affiliations": [
        "Centre de recherche du CHU de Québec-Université Laval Site CHUL, Québec City, Quebec, Canada",
        "Institut national de santé publique du Québec, Québec City, Quebec, Canada"
      ],
      "name": "Nicholas Brousseau"
    },
    {
      "affiliations": [
        "OriginElle Fertility Clinic and Women’s Health Center, Montreal, Quebec, Canada"
      ],
      "name": "Shu Qin Wei"
    },
    {
      "affiliations": [
        "Médecine sociale et préventive, Université Laval Faculté de Médecine, Québec City, Quebec, Canada",
        "Centre de recherche du CHU de Québec-Université Laval Site CHUL, Québec City, Quebec, Canada"
      ],
      "name": "Denis Talbot"
    },
    {
      "affiliations": [
        "Centre de recherche du CHU de Québec-Université Laval Site CHUL, Québec City, Quebec, Canada",
        "Pédiatrie, Université Laval, Québec City, Quebec, Canada"
      ],
      "name": "Amélie Boutin"
    },
    {
      "affiliations": [
        "Department of Epidemiology, Biostatistics and Occupational Health, University of Montreal, Montreal, Quebec, Canada"
      ],
      "name": "Caroline Quach"
    },
    {
      "affiliations": [
        "Marshfield Clinic Research Institute, Marshfield, Wisconsin, USA"
      ],
      "name": "Sarah Jorgensen"
    },
    {
      "affiliations": [
        "CHU Sainte-Justine, Montreal, Quebec, Canada",
        "Université de Montréal, Montreal, Quebec, Canada"
      ],
      "name": "Isabelle Boucoiran"
    }
  ],
  "title": "Safety of COVID-19 vaccines among pregnant individuals in Quebec, Canada: a population-based retrospective cohort study from the Canadian Immunization Research Network",
  "uid": "9ccdf870-efad-5fd2-ad86-0c39729b293b"
}