Contrasts and Pregnancy

02/08/2017 18:47

Thinking in a didactic and simple way, there are two families of contrasts: computed tomography (iodinated) and magnetic resonance imaging (gadolinium)
During pregnancy, both CT and MRI scans should be well evaluated and debated between the patient, obstetrician and imaging / radiologist.

Under exceptional circumstances, when tomography studies are essential, iodinated contrast may be used. However, following the administration of iodinated contrast to the pregnant woman, the thyroid function of the fetus should be assessed over the first week of life.

When there is a very clear indication to perform Magnetic Resonance Imaging with contrast in a pregnant woman, it is recommended to take one of the most stable gadolinium agents (with Nephrogenic systemic fibrosis).

Just to keep you in the eye, gadoliniums with a low risk of inducing "systemic nephrogenic fibrosis" are: Gadoteridol, Gadobutrol and Meglumine Gadoterate. I'll explain better on another topic.

Why these measures?

Iodinated contrast (CT) crosses the human placental barrier. gadolinium (resonance) has transplacental passage in primates . However, there are no well-controlled studies confirming teratogenic or mutagenic action ("genetic damage to the baby").

There are rare reports of hypothyroidism ("low thyroid function") associated with "old amniofetography" examination (not performed in the current routine) with the injection of iodinated contrast. However, it is not well documented that maternal intravascular (CT) contrast injection with cases of neonatal hypothyroidism ("in the baby") is not well documented.

A study (2007) with women who were exposed to gadolinium (contrast resonance) in the first trimester of pregnancy did not show a teratogenic or mutagenic effect in their newborns . But the real risk of developing "systemic nephrogenic fibrosis" in the "mother or child" is unknown.

In summary, it is important that the attending physician and the pregnant woman discuss the potential risks and benefits of using contrasts during pregnancy; and if you have any questions, before requesting any imaging examination, consult the imaging physician you trust about the best alternatives for the diagnosis in question.

The information posted on this site should not be considered medical advice. Do not forget that Medicine is a science in constant transformation and countless works and evidences are modified every day.
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