Pregnancy, breastfeeding and fertility while having trastuzumab - Brand names: Herceptin, Herzuma, Kanjinti, Ontruzant, Trazimera, Zercepac

Trastuzumab and pregnancy

It's important not to get pregnant while taking trastuzumab and for at least 7 months after treatment stops.

Trastuzumab is not recommended during pregnancy as it can affect amniotic fluid levels and this can potentially affect the baby. In rare cases, trastuzumab might need to be used during pregnancy so that the cancer does not come back.

Trastuzumab and breastfeeding

Trastuzumab is not recommended while you're breastfeeding.

There's no information on how trastuzumab passes into breast milk and what effect this might have on your baby.

Trastuzumab and fertility

There's no evidence to suggest that taking trastuzumab reduces fertility in either men or women.

For more information about how trastuzumab can affect you and your baby in pregnancy, visit the Best Use of Medicines in Pregnancy (BUMPS) website.