- Pregnant women are excluded from this study because sorafenib has the potential for teratogenic or abortifacient effects as shown by the gross fetal malformations and effects on embryo-fetal survival seen in reproductive toxicity studies in the rat. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with sorafenib, breastfeeding should be discontinued if the mother is treated with sorafenib.