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Risks From Medical Tests and Treatments During Pregnancy

Some medical tests and treatments can severely harm an unborn child and cause birth defects.

Young women are starting their menstrual periods at younger ages. Some medical treatments delay the age you start your period. For these reasons, it is important to give pregnancy tests starting at the age of 10 years.

If you are having sex:

  • You can get pregnant even if you have not yet started your periods.
  • You could get pregnant even if your medical treatments made your periods stop.
  • Always tell a member of your care team no matter your age.
Pregnancy test

Your health care team may do a pregnancy test to help protect an unborn child. Tell your care team if you are having sex.

Which tests and treatments harm an unborn child?

Some treatments and tests can harm an unborn child, such as:

In the United States, the Food and Drug Administration (FDA) works to help keep women safe when they are pregnant and taking medications. The FDA put medications into five groups (known as categories A, B, C, D, and X). The group letters tell you how much the medicine could harm an unborn child. If you are pregnant, there are two types of medicines you should know about:

"D" medicines might harm an unborn child. If you are pregnant and have a serious disease, the chance that the medicine will help you is more than the risk of harming your child. Your doctor will talk with you and help you decide if taking the medicine is worth the risk.

  • "X" medicines cause birth defects or harm to an unborn child. You should not use these kinds of drugs if you are pregnant.

Tell your care team if you have had sex within the last nine months. They will do a pregnancy test. You need pregnancy testing before you get any other tests or treatments. Your care team needs to know the test results.

Image of fetus

Some tests and treatments can harm an unborn child and cause birth defects.

Treatments and menstrual periods

  • Chemotherapy, radiation therapy, bone marrow transplants, and other treatments can change how often you get periods.
  • Some treatments may stop your periods.
  • Your care team might give you medicines that stop your periods on purpose.
  • If you do not have periods yet, they might start later than normal after treatment.

You can get pregnant even if you don't have periods

If you have sex, you can get pregnant. Medical treatments may affect your periods. But they will not keep you from getting pregnant. Some birth control methods are very effective. But there is always a risk of pregnancy even if you use birth control.

Tell your care team if you are sexually active

Tell your care team if you are having sex, have had sex within the last nine months, or are planning on having sex.

You must tell someone on your care team before getting any tests or treatments. 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. Your care team needs to know if you are having sex, so they can protect you and your unborn child if you are pregnant. They can help you make wise choices about your sexuality when you are getting treatment

Patient speaking to care team

Tell your care team if you are sexually active before you receive treatment or tests.

If you are having sex, your care team will:

  • Check to see if you are pregnant
  • Help you talk with your parents or caregivers about your test results if needed

If you are pregnant, your care team will:

  • Treat you if possible
  • Talk to you about any changes to your treatment
  • Ask you to take a break from treatment to protect your unborn child if needed

What if I have already started tests and treatment?

Even if you have already started tests or treatment, please tell your care team about your sexual activity. This information is important. It helps them pick the best treatment and care. They keep your information private unless there is a serious medical reason to tell a parent or caregiver. Don't be afraid to talk to your care team. They can speak with you about:

  • When it is safe to have sex, as some treatments can make your body bleed more or get more infections
  • How some medicines could affect or even harm your partner when you have sex
  • How you can reduce the chance of pregnancy and prevent sexually transmitted diseases
  • How treatments or medicines might affect you sexually
  • How cancer may affect your sexuality and any future plans to have children

For more information, see "Sexual Health During Cancer Treatment".

Key points

  • Your care team gives pregnancy tests young women over 10 to keep them, and possibly their unborn child, safe.
  • If you are sexually active, please tell your care team so they can give you the best treatment plan.
  • You can ask to speak privately to a member of your health care team.

Related topics

Sexual Health During Cancer Treatment
Dating When You Have Cancer: Points to Consider
Can I Still Have Children?
Infertility in Female Childhood Cancer Patients


Reviewed: August 2022