- Women of childbearing potential are required to have a negative serum pregnancy test (with a sensitivity of at least 25 mIU/mL) within 10-14 days and within 24 hours prior to the first dose of RO4929097 (serum or urine); a pregnancy test (serum) will be administered every 4 weeks if their menstrual cycles are regular or every 2 weeks if their cycles are irregular while on study; prior to dispensing RO4929097, the investigator must confirm and document the patient's use of two contraceptive methods, dates of negative pregnancy test, and confirm the patient's understanding of the potential of RO4929097 to cause serious or life-threatening birth defects; female patients of childbearing potential are defined as follows: