pcb Omer 2011.

Methods	Retrospective cohort study based on data from the Georgia Pregnancy Risk Assessment Monitoring System (PRAMS)
Participants	In all, 4168 pregnant women were included during 2 consecutive epidemic seasons (2004 to 2005 and 2005 to 2006), of whom 578 received influenza vaccination.
Interventions	Influenza vaccination during pregnancy
Outcomes	Small for gestational age and preterm births. Periods with different viral circulation were considered in the analysis.
Notes	"The study was partially funded through the Emory University, Global Health Institute Faculty of Distinction Fund award (recipient: SBO). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript" Government funded
Risk of bias
Bias	Authors' judgement	Support for judgement
PCS/RCS ‐ selection exposed cohort All outcomes	Unclear risk	Unclear
PCS/RCS ‐ selection non‐exposed cohort All outcomes	Unclear risk	Unclear
PCS/RCS ‐ comparability All outcomes	Unclear risk	Unclear
PCS/RCS ‐ assessment of outcome All outcomes	High risk	Interview
Summary assessment	Unclear risk	Unclear