 One 1 time a week for the first month you start taking lenalidomide, women who are able to become pregnant will have blood about 1 teaspoon drawn for a pregnancy test. Then, in females with regular menstrual cycles, blood about 1 teaspoon will be drawn for pregnancy testing about 28 days after the last dose of lenalidomide. If menstrual cycles are irregular, blood about 1 teaspoon will be drawn every 2 weeks, around 14 and 28 days after the last dose of lenalidomide. 