(Find the study in it's entirety at http://www.ajnr.org/cgi/content/full/23/1/19. There are a few different studies available, I chose this one to cite because it is very thorough and is available in its entirety )
I encourage you to google this yourselves. It is amazing how three maybe four reputable studies, which really do provide enough evidence and brain scans to support the brain shrinkage theory, have given birth to so many incredibly silly theories on the shrinking brain. I have to say firmly that I believe from a purely medical stand point that our brains shrink during pregnancy. However, I have not been provided with any evidence that shows this shrinkage leads to any other pregnancy phenomenon or symptoms. It is, what it is...
After hours of reading and studying, it is also clear to me thanks to all of the doctors, researchers and professionals that sleep deprivation, multi-tasking, the plethora of thoughts and fears that run through our minds and of course the raging hormones lead to this great "Baby Brain" phenomenon not our "Brain Shrinkage." I am still not sure I won't run around telling people my brain is shrinking so it's not my fault I'm so forgetful...I mean common...it's proven the brain shrinks, which I think clearly means, there's less room for all that important info! Hey, its ok to spread my filthy theory in person, of course I will set the record straight after a bit of fun.
My personal opinion, which is not worth a hill of Jack's magic beans, along with all of our other annoying pregnancy symptoms that we can do nothing about, since there is no "cure" besides delivery, we have to deal with both our "Baby Brains" and "Shrinking Brains" with as much class as possible. We are daft and our brains are going to shrink, moving on... Ok, sure get some sleep, eat well, slow down and try to control your thoughts. Good luck controlling the raging hormones once you have roped everything else in. I've decided our brain realestate is WAY to valuable to lease out to figuring out why we only have a limited amount to lease out!