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Treatment risks if pregnant


In recent years, girls have started having menstrual periods at younger ages. For this reason, it is St. Jude policy to screen girls for pregnancy starting at age 10. Medical treatment can sometimes keep girls from starting their periods at the usual age. But they can still become pregnant. This is true even if they have never had a period or stopped having periods because of medical treatments.

Why St. Jude checks for pregnancy

St. Jude tests every girl who could become pregnant for an important reason. Medical tests and treatments can severely harm (hurt) an unborn child.

Please talk to your daughter

For parents and caregivers: Please talk to your daughter about sex and pregnancy. She needs to know the risks of cancer tests and treatments to an unborn child.

Which tests and treatments can harm an unborn child?

These treatments, medicines, and imaging tests can seriously harm (hurt) an unborn child or cause birth defects.

  • Chemotherapy – Drugs to fight cancer,
  • Radiation therapy,
  • X-rays, CT scans, and nuclear medicine scans,
  • Any type of sedation or anesthesia – These drugs help you sleep or relax during tests or procedures, and
  • Many medicines.

The US Food and Drug Administration created a system to show how much risk a certain medicine causes an unborn baby. Medicines known to harm an unborn child are in categories “D” and “X”. The table below tells you what these categories mean.

FDA medicine categories for harm to an unborn child

Category Description
 D There is evidence of risk to the unborn child. However, benefits in certain serious cases may make it OK to use the drug during pregnancy despite its risks. The doctor will help decide if the benefits outweigh the risks.
There is evidence in animals or humans of birth defects or other risks to the unborn child. The drug is not used during pregnancy because it will probably cause more harm to the unborn child than it will benefit the patient.

How cancer treatment can affect menstrual periods

Chemotherapy, radiation therapy, bone marrow transplants, and other treatments can change how often you have your menstrual periods. Or it can stop them completely. Your St. Jude team might also give you medicines to stop your periods on purpose.

If you do not have periods yet, they might start later than they normally would have.

You can become pregnant even if you don’t have periods

If you have sex, you can become pregnant. Having medical treatments will not keep you from getting pregnant. Some birth control is very effective, but there is no 100 percent effective birth control method.

What to do if you have sex

Please talk to one of your St. Jude team members privately. It is important to do this before you have any tests or treatments. You can talk to a nurse, nurse practitioner, physician’s assistant, doctor, X-ray technologist, radiologist, social worker, or child life specialist. We will keep your information private unless there is a serious medical reason to tell a parent or caregiver.

You can also call the St. Jude Help Line (901-595-2999) if it is easier for you. Your doctor needs to know you have sex, so we can protect you and the unborn child if you are pregnant.

How we help keep you safe

We will check for pregnancy. If you are pregnant, we might need to change your treatment or take a break to protect your unborn baby. But we can still treat you. We can also help you talk with a parent or caregiver about your test results, if you need to. Your St. Jude team will talk with you before making any changes to your treatment.

What if you already started tests and treatment?

It is still important to tell someone, even if you already started tests or treatment. Knowing whether you are pregnant helps us plan the rest of your treatment and later care. Please help us protect your unborn child. Tell a St. Jude team member if there is any chance that you could become pregnant. We will keep your information private unless there is a serious medical reason to tell a parent or caregiver.

Avoiding a delay in your treatment

The only way to make sure an unborn child is safe is to be sure you are not pregnant before treatment. If you might be pregnant, please tell a St. Jude team member when you check in to your primary clinic. We will order a urine or blood test right away. You need this test before having any other tests or treatments.

Having a pregnancy test might delay other tests or treatments until we know the result.


To learn more about treatment risks to an unborn child, please talk to your St. Jude doctor or another team member you trust. If you are in the Memphis area, call 901-595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833) and press 0 when the call is connected.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).