Results on exposure during pregnancy from a pregnancy registry for AS04-HPV-16/18 vaccine

To assess pregnancy outcomes after exposure to AS04-HPV-16/18 vaccine (Cervarix, GSK, Belgium) prior to, or during pregnancy, as reported to a pregnancy registry.

A pregnancy exposure registry was established to collect data in the United Kingdom and the United States. Exposure was defined as vaccination with AS04-HPV-16/18 within 60days before the estimated conception date and delivery. Reporting was voluntary.

Between September 2007 and November 2015, 306 pregnancy exposure reports were received of which 181 were prospective, evaluable reports. From these 181 reports, 154 (85.1%) pregnancies resulted in a live birth, 14 (7.7%) in spontaneous abortion, one (0.5%) in stillbirth, and 12 (6.6%) were electively terminated. There was no clustering of outcomes with respect to the timing of exposure. There were 18 infants born with a congenital anomaly of which nine were minor structural defects, seven were major structural defects, one was a hereditary disorder and one was likely the result of a congenital infection. In three cases of structural defect (two minor and one major), there was a temporal association to vaccination during the critical developmental period of gestation. There was no cluster or constellation of congenital anomalies suggestive of possible teratogenesis.

The pharmacovigilance plan to investigate the effects of inadvertent exposure to AS04-HPV-16/18 vaccine during pregnancy included assessment of pregnancy outcomes among women enrolled in clinical trials, evaluation of pregnancy exposure reports from all countries as part of routine passive safety surveillance, a large, well conducted post-authorization observational study, and the pregnancy registry. These registry data complement other data from clinical trials and post-marketing surveillance showing no evidence that vaccination with AS04-HPV-16/18 during the defined exposure period (within 60days before conception until delivery) increases the risk of teratogenicity.