Association between maternal mRNA covid-19 vaccination in early pregnancy and major congenital anomalies in offspring: population based cohort study with sibling matched analysis
Bibliographic record
Abstract
Objective: To examine the association between maternal mRNA covid-19 vaccination during the first trimester of pregnancy and the prevalence of major congenital anomalies in offspring. Design: Population based cohort study with sibling matched analysis. Setting: Multiple health administrative databases, linked and analysed at ICES, an independent, non-profit research institute that collects and analyses healthcare and demographic data, Ontario, Canada, from 16 October 2021 to 1 May 2023. Population: 174 296 singleton live births >20 weeks' gestation with an expected birth date between 16 October 2021 and 1 May 2023: 34 181 (20%) born to mothers who received one or two doses of an mRNA covid-19 vaccine in the first trimester and 34 951 (20%) born to mothers who did not receive a vaccine before or during pregnancy. The sibling matched analysis included 13 312 infants exposed to a covid-19 vaccine in the first trimester and 15 089 matched older siblings with the same mother, with an expected birth date after 16 October 2016 and no reported in utero exposure to a covid-19 vaccine. Main outcome measures: Major congenital anomalies, overall and grouped by specific organ systems, diagnosed within 28 days of birth. Results: Major congenital anomalies were present in 832 (24.3 per 1000 live births) infants exposed to an mRNA covid-19 vaccine in the first trimester compared with 927 (26.5 per 1000 live births) infants not exposed to a vaccine, resulting in an adjusted prevalence ratio of 0.89 (95% confidence interval (CI) 0.79 to 1.01). Major congenital anomalies were present in 283 (21.3 per 1000 live births) and 343 (22.7 per 1000 live births) infants exposed to an mRNA covid-19 vaccine in the first trimester and their older siblings not exposed to a vaccine, respectively (adjusted prevalence ratio 0.91, 95% CI 0.77 to 1.07). First trimester vaccination was not associated with an increase in major congenital anomalies grouped by specific organ system in the primary or sibling matched analyses. Results were similar across a range of subgroup and sensitivity analyses. Conclusions: In this large population based cohort study and sibling matched analysis, mRNA covid-19 vaccination during the first trimester of pregnancy was not associated with an increase in major congenital anomalies in offspring, overall or grouped by organ system.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".