- If female and of child bearing potential, the patient has a negative serum pregnancy test within 14 days of starting therapy, and, if male or female and of child bearing potential, currently uses (and agree to continue to use throughout the study) an acceptable method of birth control (IUD, oral contraceptive, or barrier device). They should agree to continue to use these for three months after the study is completed. The patient also agrees to refrain from nursing during the duration of the study and for at least two months after the study is completed. Pregnant or lactating females are not included because the anti-proliferative effects of bevacizumab may be harmful to the fetus or developing infant.