- The effects of eribulin mesylate, trastuzumab, and pertuzumab on the developing human fetus are unknown. Pre-clinical data was suggestive of a teratogenic effect of eribulin mesylate. Pertuzumab caused oligohydramnios, delayed renal development and embryo-fetal deaths in pregnant cynomolgus monkeys. In the post-marketing setting, cases of oligohydramnios, some associated with fatal pulmonary hypoplasia of the fetus have been reported in pregnant women receiving trastuzumab. For these reasons women of child bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.