- Women of childbearing potential must have a negative qualitative serum pregnancy test ≤ 2 weeks prior to study entry. A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: 1) Has not undergone a hysterectomy or bilateral oophorectomy; or 2) Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months).