Adverse events following administration to pregnant women of influenza A (H1N1) 2009 monovalent vaccine reported to the Vaccine Adverse Event Reporting System.

ABSTRACT

OBJECTIVE: The objective of the study was to evaluate and summarize reports to the Vaccine Adverse Event Reporting System (VAERS), a spontaneous reporting system, in pregnant women who received influenza A (H1N1) 2009 monovalent vaccine to assess for potential vaccine safety problems. STUDY DESIGN: We reviewed reports of adverse events (AEs) in pregnant women who received 2009-H1N1 vaccines from Oct. 1, 2009, through Feb. 28, 2010. RESULTS: VAERS received 294 reports of AEs in pregnant women who received 2009-H1N1 vaccine 288 after inactivated and 6 after the live attenuated vaccines. Two maternal deaths were reported. Fifty-nine women (20.1%) were hospitalized. We verified 131 pregnancy-specific outcomes: 95 spontaneous abortions (<20 weeks); 18 stillbirths (≥20 weeks); 7 preterm deliveries (<37 weeks); 3 threatened abortions; 2 preterm labor; 2 preeclampsia; and 1 each of fetal hydronephrosis, fetal tachycardia, intrauterine growth retardation, and cleft lip. CONCLUSION: Review of reports to VAERS following H1N1 vaccination in pregnant women did not identify any concerning patterns of maternal or fetal outcomes.