SynthesisVaccine2023
Safety of COVID-19 vaccines during pregnancy: A systematic review and meta-analysis.
Synthesis in Vaccine, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 47 papers, 4 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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
47 citing papers in PubMed, 4 syntheses or guidelines pooled it, 77 citations in OpenAlex.
- Safety of BNT162b2 COVID-19 Vaccine in Pregnancy: A Systematic Review.Infectious diseases and therapy · 2026Pooled it
- Expert consensus on vaccination as a primary prevention strategy for women of reproductive age, pregnant, or adulthoodRevista colombiana de obstetricia y ginecologia · 2025Guideline
- Safety and Effectiveness of COVID-19 Vaccines During Pregnancy: A Living Systematic Review and Meta-analysis.Drug safety · 2024Pooled it
- Neonatal and maternal outcomes of mRNA versus Non-mRNA COVID-19 vaccines in pregnant patients: a systematic review and meta-analysis.Revista brasileira de ginecologia e obstetricia : revista da Federacao Brasileira das Sociedades de Ginecologia e Obstetricia · 2024Pooled it
- Safety, immunogenicity and pregnancy outcomes in mothers and infants after vaccination with an adenovirus-vector COVID-19 vaccine during pregnancy.Human vaccines & immunotherapeutics · 2025Trial
- Maternal vaccination timing shapes the composition and maturation of antibody clonotypes transferred to the newborn.bioRxiv : the preprint server for biology · 2026Article
- Comparison of SARS-CoV-2 total and neutralizing antibody transfer to neonates from vaccinated mothers vs. mothers infected during pregnancy: an observational study.BMC pregnancy and childbirth · 2026Observational
- Assessment of safety and immunogenicity of a protein subunit COVID-19 vaccine (ABDALA) in pregnant women: a single-cohort, multicenter, observational ESPIRTA study.BMC pregnancy and childbirth · 2026Observational
- Clinical Course and Perinatal Outcomes of Pregnant Women with COVID-19 in Central Greece: A Prospective Cohort Study.Diseases (Basel, Switzerland) · 2026Article
- Global vaccine development.Nature medicine · 2026Review
- Opportunities and barriers for innovation at the interface of engineering and maternal-fetal medicine.Communications engineering · 2026Article
- Review
- Perception of Lebanese Obstetricians Toward COVID-19 Vaccination During Pregnancy and Breastfeeding.Cureus · 2026Article
- COVID-19-related inflammation of the placenta impedes fetal development in pregnant hamsters.Nature communications · 2026Article
- Incremental prognostic value of the fibrinogen-to-albumin ratio for adverse perinatal outcomes in preeclampsia: a dual-center retrospective cohort study.Frontiers in endocrinology · 2026Article
- Comparative immunogenicity of COVID-19 vaccination in pregnant and non-pregnant women: a real-world cohort study.Frontiers in public health · 2026Article
- Immunology of RNA-based vaccines: The critical interplay between inflammation and expression.Molecular therapy : the journal of the American Society of Gene Therapy · 2025Review
- Properties and performance of a questionnaire assessing COVID-19 vaccine knowledge and attitudes in Brazilian pregnant women.BMC public health · 2025Article
- Stillbirth Discourse on Instagram and X (Formerly Twitter): Content Analysis.JMIR infodemiology · 2025Article
- Pregnancy reduces COVID-19 vaccine immunity against novel variants.NPJ vaccines · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
21 authors at 10 institutions in 6 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundAssessment of COVID-19 vaccines safety during pregnancy is urgently needed.
methodsWe conducted a systematic review and meta-analysis to evaluate the safety of COVID-19 vaccines, including their components and technological platforms used in other vaccines during pregnancy and animal studies to complement direct evidence. We searched literature databases from its inception to September 2021 without language restriction, COVID-19 vaccine websites, and reference lists of other systematic reviews and the included studies. Pairs of reviewers independently selected, data extracted, and assessed the risk of bias of the studies. Discrepancies were resolved by consensus. (PROSPERO CRD42021234185).
resultsWe retrieved 8,837 records from the literature search; 71 studies were included, involving 17,719,495 pregnant persons and 389 pregnant animals. Most studies (94%) were conducted in high-income countries, were cohort studies (51%), and 15% were classified as high risk of bias. We identified nine COVID-19 vaccine studies, seven involving 309,164 pregnant persons, mostly exposed to mRNA vaccines. Among non-COVID-19 vaccines, the most frequent exposures were AS03 and aluminum-based adjuvants. A meta-analysis of studies that adjusted for potential confounders showed no association with adverse outcomes, regardless of the vaccine or the trimester of vaccination. Neither the reported rates of adverse pregnancy outcomes nor reactogenicity exceeded expected background rates, which was the case for ASO3- or aluminum-adjuvanted non-COVID-19 vaccines in the proportion meta-analyses of uncontrolled studies/arms. The only exception was postpartum hemorrhage after COVID-19 vaccination (10.40%; 95% CI: 6.49-15.10%), reported by two studies; however, the comparison with non-exposed pregnant persons, available for one study, found non-statistically significant differences (adjusted OR 1.09; 95% CI 0.56-2.12). Animal studies showed consistent results with studies in pregnant persons.
conclusionWe found no safety concerns for currently administered COVID-19 vaccines during pregnancy. Additional experimental and real-world evidence could enhance vaccination coverage. Robust safety data for non-mRNA-based COVID-19 vaccines are still needed.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.