Is MRI safe during pregnancy?

Why MRI is preferred over CT in pregnancy

Unlike CT scans and X-rays, MRI does not use ionising radiation. Instead it relies on strong magnetic fields and radio waves, which have no proven harmful effect on the developing fetus across decades of clinical use. When imaging is medically necessary during pregnancy — for example, to evaluate appendicitis, placental abnormalities or maternal brain conditions — MRI is the recommended modality.

First trimester — what's the caution?

During the first 12 weeks, fetal organogenesis is at its most sensitive. While no studies have shown harm from MRI exposure at this stage, most international guidelines recommend deferring routine or non-urgent MRI until the second trimester. Urgent maternal conditions still warrant MRI in the first trimester — the benefit outweighs theoretical risk.

Gadolinium contrast — avoid unless essential

Gadolinium-based contrast agents cross the placenta and have been associated with rare but serious neonatal outcomes in animal and registry studies. Both the ACR and FDA advise against routine gadolinium use in pregnancy. Most pregnancy MRIs at Imaging World are performed without contrast. Your referring doctor will only order contrast if it is clinically indispensable.

What to tell the technologist

• That you are pregnant (or possibly pregnant) — at any stage
• Gestational age in weeks
• Any prior pregnancy complications
• Whether your obstetrician has reviewed the scan request
• Any implants, surgical clips, pacemakers or metal in the body

MRI for fetal evaluation

Fetal MRI is sometimes ordered as a follow-up to detailed obstetric ultrasound (anomaly scan) to better characterise central nervous system, chest or abdominal anomalies. It does not replace ultrasound but adds value when ultrasound is inconclusive. Fetal MRI is typically performed in the second or third trimester.