How to address baby shower thank-you cards?

A few people have already sent gifts from our baby registry and I am trying to get a head start on our thank-you cards. But so far, only my female relatives have listed their names on the gift receipts. In this case, should I address the thank-you just to Aunt Jane as she only listed herself as the gift-giver, or should I still address to both Aunt Jane and Uncle John?

Not sure whether this matters, but I live across the country and the majority of these relatives will not be attending baby shower in person; they are only sending a gift.