Although exercise is recommended and has several positive results, this question must be deferred to your OBGYN physician. Each pregnancy is very different and it really depends on each woman and how she is handling/carrying the pregnancy. Women that previously perform cardiovascular exercise that have no other pre-existing conditions are typically determined clear to continue their typical exercise. It is usually agreed upon that no NEW forms of exercise should be introduced during a women's pregnancy. Once again, this answer if very individualized and due to the safety of the baby, the physician must decide what is best for each patient.