Loading
Radiation can harm an unborn baby, so before your planning scan and your first treatment, anyone who could be pregnant is asked whether they might be, and before a radioactive medicine is given, whether they are breastfeeding. The answer is recorded; if pregnancy cannot be ruled out a test may be done, and if you are pregnant the team reconsiders the plan with you.
In the UK, IR(ME)R 2017 regulation 11(1)(f) requires the operator to enquire about pregnancy where relevant, and the RCR guidance (second edition, October 2026, with UKHSA) sets out how. The employer's written procedure defines who is asked (commonly people of childbearing potential aged 12 to 55, some departments 10 to 55), when (asking before the first planning exposure and before the first treatment may be sufficient), exceptions (for example after total abdominal hysterectomy), sedated or anaesthetised patients, under-16s (local safeguarding procedure), trans and gender-diverse people, and irregular cycles, where the ten-day rule and menstrual history may not predict pregnancy and routine testing may be specified. The answer is documented; a refusal to answer is documented and the unknown-status procedure followed. If pregnancy is possible or confirmed, the practitioner reconsiders justification, deferral is considered and a test is done where it cannot be excluded. For molecular radiotherapy menstrual history alone is not adequate to exclude pregnancy, and breastfeeding is completely contraindicated where the radionuclide enters milk. Deliberately treating a pregnant patient is rare, case by case, with a prior risk assessment by the medical physics expert, and AAPM TG-36 (1995) gives the physics for estimating and shielding fetal dose; an unintended fetal exposure may be notifiable.
Why: Radiation to an unborn baby can cause harm, and the law requires the person giving the exposure to ask where it is relevant.
“Regulation 11(1)(f) requires operators to enquire about pregnancy status where relevant.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026 · Legal requirement (IR(ME)R 2017)
Why: A clear rule means nobody who could be pregnant is missed and the check is not forgotten on the day treatment starts.
“It may be considered sufficient to ask prior to initial planning exposure and prior to initial treatment exposure.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
Why: People can only declare a possible pregnancy if they understand why it matters; some fear asking or answering in front of others.
“It is therefore essential to provide every individual with adequate information relating to the benefits and risks associated with the radiation dose prior to the procedure, as this gives them the opportunity to ask questions and to declare any possibility of pregnancy.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
Why: A disclosed pregnancy in a young person can raise safeguarding concerns that need a set response.
“When checking the possibility of pregnancy with individuals under 16 years of age, operators must follow the local safeguarding procedure.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026 · Must (RCR guidance)
Why: Cancer treatment and illness can stop or disturb periods, so the usual questions may not show a pregnancy.
“In these cases, the traditional ten-day rule and enquiries about menstruation may be ineffective in predicting pregnancy.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
Why: A patient who is asleep cannot be asked at the time of the exposure.
“The employer’s procedure must specify whose responsibility it is to confirm pregnancy status prior to the patient being anaesthetised or sedated.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026 · Must (RCR guidance)
Why: The record shows the question was asked and lets the team act on the answer.
“The response to pregnancy enquiries must be documented as evidence that the appropriate questions have been asked.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026 · Must (RCR guidance)
Why: A test settles the question; a radioactive medicine cannot be taken back once given.
“The confirmation of menstrual history alone is not considered adequate to exclude pregnancy.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
Why: The balance of benefit and risk changes when a pregnancy is involved, and treatment may be deferred, changed or, rarely, given with fetal shielding.
“If the possibility of pregnancy is discovered before the exposure takes place, the operator should alert the practitioner, who should reconsider justification of the exposure.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
Why: Planning and shielding can lower the dose to the fetus; the physics for estimating it is published.
“The MPE must be involved in a prior risk assessment of exposures to such individuals.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026 · Must (RCR guidance)
Why: The radioactive medicine passes into breast milk and to the baby.
“Breastfeeding is completely contraindicated for MRT using radionuclides that are excreted in breast milk.”
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
How care is usually carried out, read from the guidelines and standards cited. Your own team's protocol and their judgement come first; this page is for understanding it, not for doing it yourself.
The RCR IR(ME)R guidance for radiotherapy (second edition, October 2026, with UKHSA) is the most current and detailed source read: a written employer's procedure; an operator enquiry, documented, for all people of childbearing potential in a set age range before the first planning and first treatment exposures; sensitive, private questioning with information in advance; safeguarding for under-16s; testing where pregnancy cannot be excluded or cycles are irregular; reconsideration of justification by the practitioner with the medical physics expert if pregnancy is possible; and, for molecular radiotherapy, exclusion of pregnancy by more than menstrual history and no breastfeeding with radionuclides excreted in milk. Fetal dose estimation and shielding, where a pregnant patient is treated, rest on AAPM TG-36 (1995).
The Royal College of Radiologists, in association with the UK Health Security Agency 2026 · UK Government (legislation.gov.uk) 2017 · AAPM (Medical Physics; Stovall et al.) 1995
Where it differs: Most departments ask people of childbearing potential aged 12 to 55; some have agreed 10 to 55 with their obstetric team to fit local patients.
Evidence: Both are described by the RCR guidance as in use (12 to 55 in many departments); neither rests on a trial.
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
Where it differs: Tests everyone in the age range, or everyone with irregular cycles, rather than asking and testing only where pregnancy cannot be excluded.
Evidence: The RCR guidance leaves this to the employer's procedure after a risk assessment, and requires an appropriate test for molecular radiotherapy where pregnancy must be excluded. No comparison of approaches was found.
The Royal College of Radiologists, in association with the UK Health Security Agency 2026
Before radiotherapy, people who could be pregnant are asked whether they might be; some departments also do a pregnancy test for everyone in an age range. Which approach misses fewer pregnancies, and at what cost in delays and false alarms, has never been compared. Some cancers make the pregnancy hormone themselves and can give a false positive test.
| Recommendation | Grade, as printed | Source |
|---|---|---|
| Operators must enquire about pregnancy where relevant | Legal requirement, IR(ME)R 2017 regulation 11(1)(f) | The Royal College of Radiologists, in association with the UK Health Security Agency 2026 |
| The employer's written procedures must cover enquiries about pregnancy and breastfeeding “for making enquiries of individuals of childbearing potential to establish whether the individual is or may be pregnant or breastfeeding;” | Legal requirement, IR(ME)R 2017 Schedule 2, paragraph 1(c) | UK Government (legislation.gov.uk) 2017 |
| Making pregnancy or breastfeeding enquiries is an operator task “Making pregnancy or breastfeeding enquiries in advance of an exposure is an operator task.” | RCR guidance statement | The Royal College of Radiologists, in association with the UK Health Security Agency 2026 |
| A newly discovered pregnancy during a course leads the practitioner to reconsider justification “If the possibility of pregnancy is discovered after the exposure has been justified or during the course of treatment, the operator should alert the practitioner, who should reconsider justification of the exposure.” | RCR guidance (should) | The Royal College of Radiologists, in association with the UK Health Security Agency 2026 |
| Deliberate treatment of a pregnant patient is rare and case by case “These occasions are rare and must always be considered on a case-by-case basis.” | RCR guidance (must) | The Royal College of Radiologists, in association with the UK Health Security Agency 2026 |
| An unintended fetal exposure may need notifying “If an unintended fetal exposure occurs, this may require notification to the relevant enforcing authority in accordance with published guidance.” | RCR guidance | The Royal College of Radiologists, in association with the UK Health Security Agency 2026 |
| After molecular radiotherapy, patients are advised to avoid conception for set periods “Male and female patients who wish to conceive following treatment should be advised to avoid getting pregnant for set periods of time as recommended by ARSAC.” | RCR guidance (should), periods set by ARSAC | The Royal College of Radiologists, in association with the UK Health Security Agency 2026 |