Weighing the risks of CT scan during pregnancy
This is a difficult question and one best deferred to the surgeon dealing with the specific clinical scenario. Factors to consider include how important it is to make a definitive diagnosis before treatment can be initiated and whether or not an indefinite diagnosis would cause harm to the mother or unborn child. Will a blood test or sonogram suffice? Is laparotomy indicated anyway? How advanced is the pregnancy? In many cases, the potential risk of radiation will be clearly outweighed by the advantage of diagnosis, and as long as the mother consents, radiation should not be withheld.
In such cases, scanning techniques can still be modified; a narrow collimation with a wide pitch will reduce image quality but drastically reduce fetal exposure. Protocols can also be changed to limit the number of images obtained. For example, the precontrast series can be eliminated if contrast was ordered. For further discussion of this topic, see Kruskal JB. Diagnostic imaging procedures during pregnancy. In: Rose BD, ed. UpToDate. UpToDate Web site. www.uptodate.com. Accessed May 11, 2009.—Reuben Zimmerman, RPA-C (131-10)