IODINATED CONTRAST IN PREGNANCY  - OK
Diagnostic iodinated contrast media have been shown to cross the human placenta and enter the fetus when given in usual clinical doses . In-vivo tests in animals have shown no evidence of either mutagenic or teratogenic effects with low-osmolality contrast media (LOCM).  It is recommended that pregnant patients undergoing a diagnostic imaging examination with ionizing radiation and iodinated contrast media provide informed consent to document that they understand the risk and benefits of the procedure to be performed and the alternative diagnostic options available to them (if any), and that they wish to proceed.


GADOLINIUM IN PREGNANCY- DO NOT GIVE

A small percentage of injected gadolinium crosses the placenta and enters the fetal circulation. It is excreted into the urine and passes into the amniotic fluid, where is remains for an indeterminate time period. Therefore, given the increased likelihood that gadolinium will be released from the chelate, the free gadolinium could potentially cause neurotoxicity and produce NSF in the fetus. Therefore, the need for gadolinium injection in a pregnant patient must be carefully considered on a case-by-case basis.  No adequate and well-controlled teratogenic studies of the effects of these media in pregnant women have been performed . A single cohort study of 26 women exposed to gadolinium chelates during the first trimester of pregnancy showed no evidence of teratogenesis or mutagenesis in their progeny.


CONTRAST AND BREASTFEEDING - OK
Both iodinated and gadolinium contrast agents may be given to breastfeeding patients for indicated studies.  If the mother remains concerned about any potential ill effects to the infant, she may abstain from breast-feeding for 24 hours with active expression and discarding of breast milk from both breasts during that period . In anticipation of this, she may wish to use a breast pump to obtain milk before the contrast study to feed the infant during the 24-hour period following the examination  

IODINATED CONTRAST IN BREASTFEEDING
The plasma half-life of intravenously administered iodinated contrast medium is approximately 2 hours, with nearly 100% of the media cleared from the bloodstream within 24 hours . Because of its low lipid solubility, less than 1% of the administered maternal dose of iodinated contrast medium is excreted into the breast milk in the first 24 hours.  Because less than 1% of the contrast medium ingested by the infant is absorbed from its gastrointestinal tract, the expected dose absorbed by the infant from the breast milk is less than 0 .01% of the intravascular dose given to the mother.
 
GADOLINIUM IN BREASTFEEDING
Like iodinated contrast media, gadolinium contrast media have a plasma half-life of approximately 2 hours and are nearly completely cleared from the bloodstream within 24 hours.

Less than 0 .04% of the intravascular gadolinium dose given to the mother is excreted into the breast milk in the first 24 hours. Because less than 1% of the contrast medium ingested by the infant is absorbed from its gastrointestinal tract, the expected dose absorbed by the infant from the breast milk is less than 0 .0004% of the intravascular dose given to the mother.  The potential risks to the infant include direct toxicity (including toxicity from free gadolinium, because it is unknown how much, if any, of the gadolinium in breast milk is in the unchelated form) and allergic sensitization or reaction, which are theoretical concerns but have not been reported.


References
American College of Radiology Manual on Contrast Media, Version 7, 2010
Dean PB . Fetal uptake of an intravascular radiologic contrast medium . Rofo 1977; 127:267–270 .
2 . Kanal E, Barkovich AJ, Bell C, et al . ACR guidance docu- ment for safe MR practices: 2007 . AJR Am J Roentgenol 2007; 188:1447–1474 .
3 . Moon AJ, Katzberg RW, Sherman MP . Transplacental passage of iohexol . J Pediatr 2000; 136:548-549 .
4 . Panigel M, Wolf G, Zeleznick A . Magnetic resonance imaging of the placenta in rhesus monkeys, Macaca mulatta . J Med Primatol 1988; 17:3–18