Hmm, that's a tough one since you aren't actually pregnant yet. I feel like it would be less of an issue if you were pregnant and just needed to avoid exposure, and I can only think this would be an issue at all during surgery. It's the only time I can think of that I was required to be in a room with fluoro.
Also, just asking, but is there a reason you're set on being pregnant smack in the middle of 3rd year instead of perhaps waiting for the end of 3rd/beginning 4th? I'm currently 6 months pregnant with my 2nd child and I was lucky to have nature agree with my timing (1st to be born before 3rd year started and 2nd to be born after interview season ended). I, above all, did NOT want to be pregnant during 3rd year rotations because I wanted to be at my best at that time and had no idea what type of sickness/pregnancy brain/complications might arise. The last thing you want to do on 3rd year rotations is bomb a shelf due to "morning sickness/pregnancy brain" or ask to be dismissed, and with both my pregnancies I felt like sleeping a ton, and usually I only sleep about 5 hours a day (when not pregnant). Of course, every pregnancy is different, so you never know.
Is there any way you can at least wait until your surgery rotation is over, or is that your last one?