- The effects of RO4929097on the developing human fetus at the recommended therapeutic dose are unknown; for this reason and because Notch signal pathway inhibitors are known to cause interruption of the embryonic signaling pathway and may lead to serious or life-threatening birth defects, including brain deformities, facial malformation, heart problems, or abnormal organs; if women of childbearing potential do not abstain* from sexual activity they must use two forms of contraception (i.e., barrier contraception and one other method of contraception) at least 4 weeks prior to study entry; women of childbearing potential can either be abstinent or use two forms of contraception for the duration of study participation and for at least 12 months post-treatment; should a woman become pregnant or suspect she is pregnant while she is participating in this study and for 12 months after study participation, the patient should inform the treating physician immediately