Trastuzumab
PrintWhat is it?
Trastuzumab is an antibody therapy used to treat breast and stomach cancers.
Benefits
What are the benefits of using trastuzumab in pregnancy?
Trastuzumab can reduce certain types of tumour growth. It is only used in pregnancy when the benefits to the mother’s health outweigh the possible risks to the baby.
Risks
What are the risks of using trastuzumab in pregnancy?
Very few pregnant women taking trastuzumab have been studied. The available information does not link trastuzumab use to miscarriage or birth defects. Ongoing data collection is needed to determine whether trastuzumab is safe to take in early pregnancy.
Trastuzumab used in later pregnancy can reduce the amount of fluid around the baby in the womb. This can be linked to problems with the baby’s lungs and kidneys. It also increases the chance of the baby being born preterm, which itself poses some risks.
Alternatives
Are there any alternatives to using trastuzumab in pregnancy?
Possibly. Switching to a different drug or having a break from treatment may be an option for some women. However, if trastuzumab was working before pregnancy and there is a high chance of relapse without trastuzumab, it may be advisable to continue taking it.
Women who accidentally conceive while taking trastuzumab should arrange to see their doctor or specialist as soon as possible to make sure that trastuzumab is still the best treatment and the dose is correct.
No treatment
What if I prefer not to take trastuzumab during pregnancy?
If a woman is advised to continue trastuzumab in pregnancy, this is because she could become seriously unwell without it.
A doctor will only prescribe medicines when absolutely necessary and will be happy to talk through any concerns.
Will I or my baby need extra monitoring?
As part of routine antenatal care, most women will be offered a very detailed scan at around 20 weeks of pregnancy to check the baby’s development. No further scans to check for birth defects will be required. However, because trastuzumab used in later pregnancy can affect the amniotic fluid level, additional monitoring of this, along with the baby’s growth and wellbeing, will be recommended.
Are there any risks to my baby if the father has used trastuzumab?
There is currently no evidence that trastuzumab used by the father can harm the baby through effects on the sperm.
Who can I talk to if I have questions?
If you have any questions regarding the information in this leaflet, please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.