Aims: The aim of this study was to investigate the current prenatal "off-label use" of cytomegalovirus hyperimmunoglobulin (CMV-HIG) in the prevention and treatment of congenital CMV (cCMV) infection, including the long-term outcome of the children.

Methods: This retrospective observational study comprised mothers and their children, born between January 1, 2006, and October 30, 2010. Prenatal CMV-HIG was administered after diagnosis of primary CMV infection of the mother. Clinical and virological data were collected from maternal and pediatric medical and laboratory reports. Follow-up was 12-36 months after birth.

Results: Forty-two women and 43 children met the study criteria. In total, 40 mothers and six unborn infants received 115 doses of CMV-HIG. The treatment group (TG; CMV-DNA polymerase chain reaction-positive amniotic fluid) included four mothers; the multinomial group (MG; CMV-positive mother and unknown CMV status of fetus) included 38 mothers (39 infants). For the four unborn infants in TG, CMV-HIG was administered either intraumbilically or into the amniotic fluid; three of the four mothers received intravenous CMV-HIG. Three children in TG remained CMV-positive and were asymptomatic at birth and during follow-up. One infant in TG had symptomatic cCMV infection in utero, at birth, and during follow-up. In MG, 37 of 38 women received intravenous CMV-HIG and two of 39 infants received CMV-HIG in utero. In total, 9 (23.1%) of 39 children in MG were positive for cCMV (including a terminated pregnancy). All eight instances of cCMV infection at birth in MG were asymptomatic at birth and during follow-up. The fetus from the terminated pregnancy showed no sonographic symptoms of cCMV infection. No severe side effect occurred in 115 CMV-HIG applications.

Conclusion: CMV-HIG was well tolerated. Compared with published untreated mother-child pairs, we observed a trend toward a smaller risk for intrauterine CMV transmission following CMV-HIG application. Signs of prenatal cCMV disease were not reversed after CMV-HIG.