My mother too has thyroid problems but they were not manifest until just a few years ago. However, she has told me that her doctor had prescribed uppers for her while she was pregnant for me.
We search in vain for a reason. We, as outsiders to the medical profession, can only stand by and hope for the kind of research that will show why. But you know.... it doesn't matter. Here we are and there is the issue/problem. Ya gotta deal with it hon. There are tools to do that. It's called money.
Cindi