This PROSPERO-registered systematic review evaluated the safety of BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine in pregnant women, covering 25 studies published December 2020–June 2025, with outcomes including miscarriage, congenital anomalies, preterm birth, hypertensive disorders, small for gestational age (SGA), low birth weight, and neonatal death.
Across 25 studies comprising >450,000 BNT162b2-vaccinated pregnant women, no increased risk was found for any of the evaluated obstetric or neonatal outcomes; effect estimates were broadly consistent and centered around the null across trimester-stratified analyses, dose numbers, and study designs.
- Evidence is predominantly observational and heterogeneous, limiting causal inference. - Data on first-trimester-specific exposure were sparse, leaving precision limited for this critical window. - Limited precision for rare outcomes due to study-level sample constraints.
Clinicians can reassure pregnant patients that BNT162b2 vaccination shows no signal of increased obstetric or neonatal harm across a large and varied evidence base. First-trimester counseling should acknowledge that data for that window remain more limited than for later pregnancy.
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