Gadolinium-based contrast agents cross which of the following during pregnancy?

Gadolinium-based contrast agents cross which of the following during pregnancy?

• A. Blood-brain barrier
• B. Lungs
• C. Liver
• D. Placenta

Answer: (D)

Gadolinium-based contrast agents can cross the placenta, reaching the fetus. The placenta is the site of maternal–fetal exchange, so substances present in maternal blood can cross into fetal circulation through it. This is why gadolinium-based agents are avoided in pregnancy unless the imaging result is essential. The other options aren’t the routes for fetal exposure in this context: the blood-brain barrier governs entry to the brain, not fetal transfer; the lungs and liver are maternal organs, not pathways for the fetus.

Gadolinium-based contrast agents can cross the placenta, reaching the fetus. The placenta is the site of maternal–fetal exchange, so substances present in maternal blood can cross into fetal circulation through it. This is why gadolinium-based agents are avoided in pregnancy unless the imaging result is essential. The other options aren’t the routes for fetal exposure in this context: the blood-brain barrier governs entry to the brain, not fetal transfer; the lungs and liver are maternal organs, not pathways for the fetus.