I have not had a root canal while pregnant but I have had six root canals in my lifetime (you'd think I never brush my teeth or something, but I have been told I over brush them).
Anyways, be sure to check with your obgyn and see what his/her advice is regarding root canals during pregnancy. Often times the obgyn has more experience in illnesses, etc. than you realize and may know of the best treatment plan for you .
As for the drilling and scraping, there is A BUNCH OF IT during a root canal!!! All of the tooth has to be drilled down to the root and it is very intensive, if you have a smaller mouth, you will have a very hard time with the root canal while you are pregnant...it's a lot of pressure on your jaw and, for someone who is not good at the dentist, I'm sure it would be a lot of pressure on your body.
Some people say they feel better after a root canal and some people say they hurt for a while. As for me, I always hurt for the first day (i have a smaller mouth and my jaw always hurts afterwards), then my tooth is sensitive for about a month afterwards and I can't use that side of my mouth to chew.
Good luck, I pray you will have comfort and that your baby will be safe no matter what!