Description: Publication date: 15 January 2015 Source: Vaccine, Volume 33, Issue 4 Author(s): Pedro L. Moro , Yenlik Zheteyeva , Paige Lewis , Jing Shi , Xin Yue , Oidda I. Museru , Karen Broder Background In 2006, quadrivalent human papillomavirus (HPV4; Gardasil, Merck & Co., Inc.) vaccine was licensed in the US for use in females aged 9–26 years. HPV4 is not recommended during pregnancy; however, inadvertent administration during pregnancy may occur. Objectives To evaluate and summarize reports to the Vaccine Adverse Event Reporting System (VAERS) in pregnant women who received HPV4 vaccine and assess for potentially concerning adverse events among non-manufacturer reports. Methods We searched the VAERS database for non-manufacturer reports of adverse events (AEs) in pregnant women who received HPV4 vaccine from 6/1/2006 to 12/31/2013. We conducted clinical review of reports and available medical records. Results We found 147 reports after HPV4 vaccine administered to pregnant women. The most frequent pregnancy-specific AE was spontaneous abortion in 15 (10.2%) reports, followed by elective terminations in 6 (4.1%). Maternal fever was the most frequent non-pregnancy-specific AE in 3 reports. Two reports of major birth defects were received. No maternal deaths were noted. One hundred-three (70.1%) reports did not describe an AE. Conclusions This review of VAERS non-manufacturer reports following vaccination with HPV4 in pregnancy did not find any unexpected patterns in maternal or fetal outcomes.