Gadolinium in Pregnant patients ?

Magnetic resonance imagining (MRI) is considered safe during pregnancy, as magnetic energy has been shown not to be harmful for the developing fetus

Iodinated diagnostic contrast media have been shown to cross the human placenta and enter the fetus in measurable quantities. Gadolinium crosses the placenta and enters the fetal circulation, where it remains for an indefinite amount of time (it is excreted by the fetal kidney then swallowed by the fetus in amniotic fluid).  It is then possible that a small amount will be absorbed from the gut of the fetus and the rest eliminated back into the amniotic fluid, the entire cycle being repeated innumerable times. There are no data available to assess the rate of clearance of contrast media from the amniotic fluid. 

--> A standard gadolinium-based MR contrast medium has been shown to cross the placenta in primates and appear within the fetal bladder within 11 minutes after intravenous administration Mutagenic effects of gadolinium have been demonstrated in animal studies, but no evidence for tetratogenic or mutagenic effects have been noted in humans so far. The use of gadolinium is to be avoided in the first trimester.


The ACR Guidance Document for Safe MR Practices  also covers use of MR contrast media in pregnant patients, and its recommendations are consistent with those in this Manual. See also the preceding Chapter on NSF (www.acr.org/SecondaryMainMenuCategories/quality_safety/contrast_manual/NephrogenicSystemicFibrosis.aspx)

Because it is unclear how gadolinium-based contrast agents will affect the fetus, these agents should be administered only with extreme caution. Each case should be reviewed carefully and gadolinium-based contrast agent administered only when there is a potential overwhelming benefit to the patient or fetus that outweighs the possible risk of exposure of the fetus to free gadolinium ions. The radiologist should confer with the referring physician and document the following in the radiology report or the patient’s medical record: 
1. That information requested from the MR study cannot be acquired without the use of IV contrast or by using other imaging modalities. 
2. That the information needed affects the care of the patient and fetus during the pregnancy.
3. That the referring physician is of the opinion that it is not prudent to wait to obtain this information until after the patient is no longer pregnant. 

It is recommended that the pregnant patient undergoing an MR examination provide informed consent to document that she understands the risk and benefits of the MR procedure to be performed, and the alternative diagnostic options available to her (if any), and that she wishes to proceed. 

The European Society of Radiology has issued a guideline19 discussing gadolinium use during pregnancy. Their conclusion is that gadolinium is probably safe during pregnancy, as excessive quantities are not expected to cross the placenta or to be toxic to the fetus if they do. These guidelines also state that, given that gadolinium is mainly distributed in extracellular water and rapidly eliminated by the kidney, in the unlikely event that some gadolinium reached the baby, it would be rapidly eliminated into urine.