Maternal immunization: an update for pediatricians.

The immunization of women during pregnancy can protect both the mother and her infant against serious infectious diseases. The prevention of infection through maternal immunization reduces the risk of exposure to the baby, results in higher concentrations of transplacentally transferred pathogen-specific maternal antibodies to the newborn, and provides protection to the infant during a period of vulnerability. The benefits of vaccinating pregnant women outweigh any theoretic risk when there is a risk of exposure to an infectious disease that threatens the mother or the newborn's health. Toxoids and inactivated virus or bacterial vaccines are safe and cause no harm to the mother or fetus. Live vaccines, viral or bacterial, are contraindicated during pregnancy as a precaution because of the theoretic risk of infection of the fetus. However, there has been no evidence to date of direct fetal injury after the administration of live viral vaccines to pregnant women. The administration of immune globulin preparations to pregnant women results in no known risks to the fetus. In the United States, vaccines recommended in pregnancy include the seasonal influenza vaccine, tetanus toxoid, and the pertussis vaccine as a combined tetanus-diphtheria toxoid and acellular pertussis vaccine (Tdap). Pregnant women who travel or who have unavoidable exposures to vaccine-preventable diseases should be immunized. Breast-feeding is not a contraindication to the vaccination of mothers with inactivated and most live vaccines. Women who are not immune to rubella should be immunized after delivery. Similarly, the influenza and Tdap vaccinations may be administered postpartum in women who were not vaccinated during pregnancy.