After taking MMR live vaccine, conception should not occur within ?

Measles-mumps-rubella (MMR) vaccine and its component vaccines should not be administered to women known to be pregnant. Because a risk to be fetus from administration of these live virus vaccines cannot be excluded for theoretical reasons, women should be counseled to avoid becoming pregnant for 28 days after vaccination with MMR vaccine or its component vaccines or varicella vaccine. Ref: Park 24th edition