After a rubella vaccination it's recommended to not get pregnant for 28 days.

On October 18, 2001, the Advisory Committee on Immunization Practices (ACIP) reviewed data from several sources indicating that no cases of congenital rubella syndrome (CRS) had been identified among infants born to women who were vaccinated inadvertently against rubella within 3 months or early in pregnancy.

On the basis of these data, ACIP shortened its recommended period to avoid pregnancy after receipt of rubella-containing vaccine from 3 months to 28 days. It's suggested not to get pregnant for 28 days after the rubella vaccine.