Over time I'm sure there is risk with radiation, however it is small. To give you an idea, to try to track a foreign body through the GI tract in dogs sometimes we will do 6-15 X-rays just in one day! And we don't worry about it because radiation sickness is very very rarely seen in animals and usually due to focus radiation for cancer treatment purposes. I wouldn't be doing them daily necessarily, but around weekly during a month span of being gravid is nothing I would worry about personally.