Bobbi
I cannot give you the definitive answer you are looking for, but I can explain a bit about what is going on with the different recommendations you have been given about how long to wait after RAI before getting pregnant.
There are two basic issues, that work together to make waiting prudent. The first, of course, has to do with any radiation exposure to the ovaries. Waiting through six to twelve months of menstrual cycles uses up eggs that were "mature" or close to mature at the time of the treatment. It is a precaution, because there is a possibility that as RAI is eliminated from the body via the kidneys and bladder, some radiation could affect the more mature eggs. It is not thought to affect those eggs which are not ready to be released. As to why there is no agreement among professionals? Your guess is as good as mine. If there were detailed clinical studies available, I would assume there would be a fair level of consistency between the advice given. This is not, however, something that has been studied with control groups, double-blind, etc., so I think the estimates we patients are given when we ask the question is the doctor’s best guess.
But, second, and also very important is the issue of your health. It can take a good six months at the very least for us to get regulated on thyroid replacement hormone, and many of us take longer. Our bodies begin to heal once we are on a dose of replacement hormone that is reasonably close to what we need . Prenancy puts strains on the body, so it is preferable that we be in good health when we become pregnant. OUt-of-whack thryoid levels can cause problems during a pregnancy, so being stabilized is a huge help. You might regulate onto replacement hormone faster than someone else — or slower. It is wise for you to wait until you’ve got reasonably good health back, and stable thyroid hormone levels, and that means probably a good 9 months if not a tad longer. You being healthy going into the pregnancy is going to be a huge help to both you and to your baby.
Bobbi – NGDF Online FAcilitator