For pregnant women still weighing the risks of COVID-19 vaccination, evidence continues to accumulate that forgoing vaccination may carry greater danger than receiving it. A large retrospective cohort now adds meaningful data on neonatal outcomes, challenging lingering hesitancy that persists even as the acute pandemic phase recedes.
Analyzing records from 4,032 pregnancies managed at a major Thai academic medical center between late 2021 and end of 2023, investigators found that the 41% of women who received at least one COVID-19 vaccine during pregnancy experienced markedly better neonatal outcomes. Maternal vaccination was associated with a 59% reduction in stillbirth risk (adjusted OR 0.41) and a 73% reduction in small-for-gestational-age (SGA) births (adjusted OR 0.27). Timing mattered considerably: vaccination during the second or third trimester was specifically associated with lower rates of abortion, stillbirth, SGA, and poor five-minute Apgar scores relative to unvaccinated pregnancies. mRNA vaccines in particular were associated with lower abortion and stillbirth rates. Completeness of vaccination also carried significance — fully vaccinated women fared better on composite neonatal outcomes than partially vaccinated counterparts.
This study sits within a growing body of evidence suggesting that COVID-19 infection itself — not the vaccine — is the primary driver of adverse obstetric outcomes including preterm birth, stillbirth, and neonatal ICU admission. Earlier registry-based studies from the U.S., UK, and Scandinavia broadly support vaccination safety in pregnancy; this Thai cohort adds heterologous and non-Western vaccination patterns to that picture. Key limitations deserve acknowledgment: the retrospective design cannot rule out residual confounding, since healthier or more health-engaged women may be more likely to vaccinate. The cohort is drawn from a single tertiary-care hospital, limiting generalizability to higher-risk or resource-limited populations. Effect sizes for SGA are notably large and warrant replication. Overall, this is a confirmatory and contextually valuable addition to the literature — particularly for regions where mRNA-vector heterologous schedules dominate — but not a paradigm shift.