ObjectiveTo evaluate the seroprevalence of the rubeola (measles) antibody in several obstetric populations.MethodsIn this cross-sectional study, women presenting for prenatal care underwent measurement of antibodies to the rubeola virus. The study population presented for care at either an urban medical center (group I) or a suburban medical center (group II). These groups were divided further into those receiving care in a resident-supervised clinic (A) and those in a private-practice setting (B).ResultsA total of 768 women were tested. Seventy-five (9.8%) women had rubeola antibody titers less than or equal to 0.13 and were classified as seronegative. The lowest percentage of seronegative women (3.2%) was found at the urban resident-supervised clinic site. The highest percent-age of seronegative women (20.5%) was found in the suburban resident-supervised clinic site. Women classified as seronegative were younger, with a mean age of 25.0 years. No significant difference was observed based on gravidity, party, or care received in an urban versus suburban private-practice setting.ConclusionWe suggest that an appreciable number of women presenting for prenatal care may lack antibodies to the rubeola virus. In the interest of personal and public health, populations believed to be at risk may benefit from ongoing surveillance of immune status and appropriate vaccination. Additional study is necessary to define best those groups that would benefit from surveillance and vaccination.