- If a female subject of childbearing potential, subject has a negative urine pregnancy test. Sexually active women of childbearing potential participating in the study must have been using a medically acceptable form of contraception (which includes barrier methods, oral contraception, injectable or implantable methods, or intrauterine devices) for at least three months prior to entry into the study. A woman of childbearing potential is defined as one who is biologically capable of becoming pregnant. Abstinence is considered an acceptable method of contraception.