Risks From Medical Tests and Treatments During Pregnancy

It is strongly recommended to wait until after treatment to have a baby. Some medical tests and treatments can be harmful during pregnancy and cause birth defects in a developing baby. These include: 

• Chemotherapy
• Radiation therapy
• Stem cell transplant
• Imaging tests such as X-rays, CT scans, and nuclear medicine scans 
• Anesthesia or sedation 
• Many medicines (ask your doctor or pharmacist) 

Use birth control

• Birth control, also called contraception, is any method used to prevent pregnancy. For a birth control product to work, it must be used correctly every time.  
• Abstinence (not having sex) is the only method that is 100% effective in preventing pregnancy. 
• Always use a birth control method recommended by your care team.  
• Some medicines and treatments can affect how well certain birth control methods work. In some cases, your care team may advise you to use 2 forms of birth control for safety, such as a hormonal birth control and condoms. 

Take a pregnancy test

Health care providers usually give a pregnancy test to anyone who could be pregnant before starting medicine, tests, or treatment that could hurt a baby. If you are old enough to have a menstrual period, your care team may give you a pregnancy test. You may get this test whether or not you are currently sexually active.  

Why are pregnancy tests important? 

• Birth control methods aren’t 100% effective. There is always a risk of pregnancy if you are sexually active. 
• Medical treatments may change, stop, or delay your periods. But not having periods does not prevent pregnancy. If you have vaginal sex, you can get pregnant — even if your periods have not started or have stopped.  
• Some treatments pose such a high risk to an unborn baby, that they require a pregnancy test before they can be given for all females of a certain age. 

Talk to your care team

Tell a health care provider if you are sexually active, even if you have already started tests or treatment.

Let your care team know if: 

• You are currently having sex 
• Have had sex within the last 9 months 
• Are planning on having sex 
• Are pregnant or breastfeeding 

Your care team can help you make choices about your sexual health when you are getting treatment to keep yourself and others safe. 

You can ask to talk privately with any member of your health care team. They will keep what you say private unless there is a serious medical reason to tell your parent or caregiver.  

Do not be afraid to talk to your care team. They can speak with you about: 

• When it is safe to have sex, since some treatments can make your body bleed more or get more infections 
• Any potential risk to your partner when you have sex and how to keep them safe 
• How to reduce the chance of pregnancy and prevent sexually transmitted infections (STIs) 
• Side effects of treatments or medicines that might affect intimacy, relationships, or sexual health 
• How cancer may affect your fertility and any future plans to have children 

For more information, see Sexual Health During Cancer Treatment. 

What if I am pregnant or planning a pregnancy? 

If a pregnancy occurs, doctors may stop therapy or change the treatment plan. This could affect your long-term health or chance of cure. 

If you are pregnant, your care team will: 

• Talk to you about the risks 
• Discuss any recommended changes to your treatment plan 
• Continue with treatment, if possible 
• Ask you to change, delay, or pause treatment to protect your unborn baby if needed 

Questions to ask your care team

• Could this test or treatment harm a pregnancy or unborn baby? 
• Is it safe to have imaging tests while pregnant? 
• Do I need a pregnancy test before this test or treatment? 
• What birth control method should I use during treatment? 
• Could any of my medicines make birth control less effective? 
• What should I do if I am worried that I might be pregnant? 
• Do I need to stop or change any of my medicines if I am pregnant or breastfeeding? 
• Can I speak to a care team member privately about this? 

Related content