Hi H.,
I am a Lactation Consultant in Sacramento, my name is J. Simpson. Talk to your Dr and find out if they plan on using a contrast dye - if so, then depending on what it is you may be able to breastfeed very soon after the procedure. Some dyes are out of your system very quickly, others take a bit longer. Docs typically do a bit of overkill on the pump and dump stuff to cover their butts...not yours. The information is out there for them to find out how long breastfeeding should or should not be interrupted...
My advice would be to find out what they are using. If nothing, then there is absolutely NO reason to interrupt breastfeeding. If they are using a contrast dye, you can research it on the La Leche League site (as suggested by another respondent - thank you!) or give me a call or your local Lactation Consultant and we can help you do that research.
As far as waiting to take care of yourself, I don't know that I agree with others who say wait, and put the breastfeeding first. This is YOUR health and you NEED to not be in pain. If you are unable to have a pain free life (and I know oh so well what that is all about) it does make it harder to enjoy our babies and care for them at times. So, I encourage you to do what you need to do for yourself and find a way to balance that with taking care of your daughter.
If you were in the Sacramento area I'd refer you to the gal who does my body work - out of 8 or so practitioners over 11 yrs she is the ONLY one who gave me back full, 100% functional use of my body - which, due to my injuries and the severity of them, I really shouldn't have. :) She helped me avoid surgery, and painful and expensive testing...she simply fixed the problems and allowed my body to heal itself and relearn how to function. She is fabulous! If you are up to the drive let me know...
Warmly,
J. Simpson, IBCLC, CIIM
www.breastfeedingnetwork.net
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