<qa>  What is the risk of pregnancy that WOCBP must have within 72 hours of the start of- Women of childbearing potential WOCBP must use medically approved methods of birth control to avoid pregnancy throughout the study and for up to four weeks after completion of the study in such a manner that the risk of pregnancy is minimized. WOCBP must have a negative serum or urine pregnancy test within 72 hours prior to the start of the study. 