In contrast to the risks and prevention of congenital rubella which are well-known in France, the problems that may result from measles, chicken-pox and mumps occurring in the course of pregnancy remain to be delineated. Our experience, based on a long-term prospective study of mothers and full-term infants born after preventive or curative administration of immunoglobulins has led us to the following conclusions. During pregnancy, as far as mumps and chicken-pox are concerned, the risk of fetal involvement seems much lower than is usually believed; however, the numerous documented reports in the medical literature show that this risk is a reality. Measles have become exceptional in adulthood. In the pre and post-partum period, the prevalence and severity of chicken-pox make it an important risk. The correct use of specific immunoglobulins and the strict isolation of affected neonates should reduce the prevalence of neonatal cases. As soon as the risk is known, immediate drastic measures must be taken, in order to achieve the isolation and immunoglobulin protection of babies, mothers and staff members who have been in contact with the infected patient. The study of specific antibodies in young women show that a large proportion of this population is currently receptive to chicken-pox and mumps. A short and long term preventive policy is needed to avoid fetal involvement and severe neonatal infections.