You can look at this link:
http://www.sec.noaa.gov/info/RadHaz.html
There is an American Doctor who gives a radio show, Dr. Dean Adell (Spelling?) that gave a show on why flight attendents should not fly when they are pregnant........but I cannot find the link for him.....
In my airline, I have flown with a few female pilots who wore radiation monitors when they were pregnant.
And I have heard, albeit hearsay, that on one occaision in this airline when the Captain asked the First Officer to get a step climb to FL 410 from ATC, the F/O replied "We can't go to 410, my Baby!!!!!"