- Patients must not be pregnant or breast feeding. Due to the potential teratogenic properties of lenalidomide, the use of this drug in patients that are pregnant is absolutely contraindicated. Further, all women of childbearing potential and sexually active males must agree to avoid conception while participating in this study. Specifically, women of childbearing potential must either agree to refrain from sexual intercourse or employ a dual method of contraception, one of which is highly effective (IUD, birth control pills, tubal ligation or partners vasectomy), and another additional method (condom, diaphragm, or cervical cap) for 4 weeks prior to receiving lenalidomide, and for four weeks after discontinuing this therapy. Sexually active males cannot participate unless they agree to use a condom (even if they have undergone a prior vasectomy) while having intercourse with a woman of child bearing potential while taking lenalidomide and for four weeks after stopping treatment. Women of child bearing potential (those who have not had a hysterectomy or the absence of menstrual periods for at least 24 consecutive months) must have a negative pregnancy test 10-14 days prior to the initiation of therapy and a repeat negative pregnancy test 24 hours prior to the initiation of lenalidomide.