Quality Initiatives: Guidelines for Use of Medical Imaging during Pregnancy and Lactation

Abstract

The use of computed tomography (CT) and magnetic resonance (MR) imaging has increased tremendously in the past 2 decades. Hence, pregnant and breast-feeding women, although generally healthier than the population at large, are also more likely to require contrast material-enhanced imaging. When a contrast-enhanced CT or MR imaging study is being considered for a pregnant or lactating patient, the potential risks to the fetus related to exposure to radiation, high magnetic fields, or contrast agents must be considered and weighed carefully against the risks of potential misdiagnosis due to withholding contrast agents and imaging studies. Fetal radiation doses up to 1 mGy are considered acceptable; with larger doses, the risk of carcinogenesis approximately doubles, although it remains low in absolute terms. No damage to a developing human fetus caused by MR imaging exposure has been documented. However, caution is advised, and risks and benefits must always be considered before evaluating a pregnant patient with MR imaging. The use of iodinated contrast agents is generally safe during pregnancy; nevertheless, these agents should be used with caution due to the risk of fetal hypothyroidism and should be administered only when the clinical situation clearly requires doing so. The use of gadolinium-based contrast agents during pregnancy remains controversial due to lack of human clinical data and potential toxicity. Use of all contrast agents is considered safe during lactation. It is hoped that this knowledge will help radiologists develop a consensus with their clinical colleagues regarding case management of pregnant and lactating patients.

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“…If the embryo survives, exposure to radiation in this early phase will probably not result in deterministic or stochastic eff ects on the foetus because blastocyst cells are omnipotent and can replace damaged cells (the so-called "all-or-none period"). The growing embryo or foetus is most vulnerable to radiation eff ects between the 8th and 15th weeks of gestation [89]. A defi nitive threshold has not been determined, but it is assumed that the risks of congenital malformations, intrauterine growth restriction, intellectual disability, and pregnancy loss substantially increase with doses greater than 100 -200 mSv [63,87].…”

“…The International Commission on Radiological Protection has estimated the increase in the risk of fatal childhood cancer before the age of 15 years old after in utero radiation exposure to be approximately 0.006 % per mSv, which corresponds to a risk of one in 17,000 cases per mSv [88]. With higher doses (e.g., 20 -50 mSv during pelvic CT), there is an estimated 2-fold increased risk of childhood cancer, but the absolute increase in lifetime cancer risk remains low and has been estimated to be less than one in 250 cases [63,89]. Considering that approximately 23 -42 % of the general population can be expected to develop cancer in their lifetime, the impact of in utero radiation exposure due to diagnostic imaging on lifetime cancer risk seems to be negligible [63,87].…”

“…No eff ect on foetal thyroid function has ever been reported, but a theoretical risk of iodine-induced neonatal hypothyroidism remains [49,89,96,97]. Although it is standard practice to screen all neonates for hypothyroidism, this test is particularly important in neonates born to women who re- Table IV.…”

“…Foetal and maternal radiation doses associated with diagnostic tests for VTE. The broad ranges of values for some tests refl ect heterogeneity in the protocols and equipment used, as well as differences in the size and age of the foetus at time of exposure [74,89] ceived iodinated contrast agents during pregnancy [98]. No animal studies have demonstrated the teratogenicity of intravascular administration of iodinated contrast media, but the current guidelines of the European Society of Urogenital Radiology (ESUR) state that iodinated contrast agents should be administered with caution because serious adverse eff ects cannot be defi nitively excluded [98].…”

“…Less than 1 % of contrast medium administered to lactating women is excreted into the breast milk, and less than 1 % in the breast milk is absorbed by the child [99]. Theoretical risks from contrast agents include direct toxicity or allergic sensitivity and reaction, neither of which has been reported [63,89].…”