No ionising radiation
MRI uses a magnetic field and radio waves, not X-rays. That is why it is sometimes chosen in pregnancy when ultrasound does not answer the question and CT would add radiation.
It is not a routine scan
Clinics do not offer MRI in pregnancy for reassurance alone. A doctor should have a clear reason: for example a suspected appendix problem, a neurological symptom, or a fetal question that ultrasound cannot settle. The referring doctor and the radiologist agree that the benefit outweighs waiting.
Contrast
Gadolinium contrast crosses the placenta. It is avoided in pregnancy unless a specialist decides the information is essential and cannot be obtained another way. Mention pregnancy, or the chance of pregnancy, on the safety form even if you are early on.
Practical points
- Tell the clinic as soon as you book.
- Lying flat for a long time can be uncomfortable later in pregnancy. Ask about breaks and positioning.
- Ear protection is still used. The noise does not reach the baby as scanner noise in the room.