OBJECTIVES

: Studies have demonstrated the effectiveness of HBV vaccination in pregnancy to reduce risk of transmission, but the risk/benefit of HBV vaccination in pregnancy has not been fully elucidated due to limited data on pregnancy outcomes. This study evaluated data on HBV vaccination in pregnancy and impact on pregnancy outcomes.

METHODS

: MEDLINE was searched in Jan 2018 using the search terms: hepatitis B vaccine, pregnancy, major congenital malformations (MCMs), preterm birth, spontaneous abortion (SAB), and fetal/neonatal death. The search identified 1 RCT, 5 prospective cohort studies, and 1 Vaccine Adverse Event Reporting System (VAERS) study; 5 of 7 studies were conducted in the 1980’s-90’s.

RESULTS

: The RCT and 2 cohort studies examined recombinant HBV vaccines in 284 pregnant women. Vaccination occurred in the 1^st trimester in the cohort studies and 3^rd trimester in the RCT. No MCMs and 1 SAB were reported. The preterm birth rate was comparable to general population rates. The other 3 cohort studies examined plasma-derived HBV vaccines in 97 pregnant women. Vaccination occurred in the 1^st trimester in 1 study and 2^nd/3^rd trimester in the other 2. No MCMs, SABs, or preterm births were reported. The stillbirth rate was comparable to the comparator (1.4 vs 1.2). The VAERS study included 192 pregnant women receiving HBV vaccines from 1990-2015. Most were vaccinated in the 1^st trimester and 110 adverse events were reported, including the following pregnancy-related events: 5 unique MCMs, 23 SABs, 1 neonatal death, 2 stillbirths, and 7 preterm births.

CONCLUSIONS

: The majority of prospective studies identified are old, have limited sample sizes, and inappropriate exposure windows. The VAERS study is recent but has limitations (recall bias, inconsistent data, lack of denominator data) due to the spontaneous/voluntary nature of the reporting of adverse events. While the data from these limited studies are reassuring, more research is needed.