Infectious mononucleosis during gestation: report of three women and their infants studied prospectively.

Epstein-Barr virus (EBV) infection during gestation has been associated retrospectively with the occurrence of fetal malformations. The referral in the first trimester of three women with infectious mononucleosis allowed us to study prospectively this question. Infectious mononucleosis was confirmed by EBV-specific serology in two women and on the basis of the heterophil antibody response and atypical lymphocytosis in the third. The titers of EBV-specific antibodies in the cord sera of the infants approximated those of the respective maternal sera drawn at the time of birth and declined in a fashion consistent with transplacental acquisition. All three women delivered healthy term infants without malformations or stigmata of congenital infection. Thus we observed no adverse effect of maternal EBV infection on these infants.