First of all, congrats to your aunt! Has your aunt discussed this early exposure with her neuro? Another place to try would be the support people for avonex…she should have a number to call when she has questions about her med.
It looks like avonex is a pregnancy category C drug, which basically means they haven’t really studied the risks. You might try googling “avonex in early pregnancy,” or something like that. When I poked around a bit using the search terms above, I found reference to an observational clinical trial studying exposure in pregnancy. It’s not yet complete though. Here is another bit of info I found while searching:
Hopefully someone else can provide you with a little more info J