Safety of MenACWY-CRM vaccine exposure during pregnancy

Although the meningococcal conjugate MenACWY-CRM vaccine is not approved for use in pregnant women, unintentional exposure during pregnancy can occur, especially during early pregnancy among women of child-bearing age. This study provides safety information about inadvertent MenACWY-CRM vaccination during pregnancy.

The evaluated population consisted of pregnant female members of Kaiser Permanente Southern California who inadvertently received MenACWY-CRM at 11-21 years of age during 09/30/2011-06/30/2013 within 28 days prior to conception or during pregnancy. Chart abstraction was conducted to identify pregnancy and birth outcomes, including spontaneous and induced abortions, preterm births, low weight births, and major congenital malformations (MCMs).

There were 92 women who received MenACWY-CRM during the pregnancy exposure period, mainly during the first trimester (76.1%). Hispanics represented the largest race/ethnicity category (68.5%). Among the known pregnancy outcomes (n = 66; excluding induced abortions and unknown pregnancy outcomes), the prevalence of spontaneous abortions was 18.2% (n = 12). Among live born infants (n = 55; from 54 pregnancies), 14.5% (n = 8) were born preterm (<37 weeks gestation) and 9.1% (n = 5) had a low birthweight (<2500 g). The prevalence rate of MCMs among live born infants (n = 55) was 1.8% (n = 1).

This study provides baseline prevalence estimates of spontaneous abortions, preterm births, low weight births, and MCMs among women inadvertently exposed to MenACWY-CRM during the pregnancy period. These estimates appear to be comparable with U.S. background prevalence estimates.