There are quite a few Thal(Minor)'s who were NOT diagonised with Thal(Trait) when the Electrophoresis was done. (It does NOT seem to be reliable in all cases). As Manal mentioned, it is a good idea to get the DNA test done to find out the confirmed results
Also, the most important thing for you right now, is to know if your husband is a Thal(Trait). Only 1 parent being a Thal(Minor) - would NOT be a major problem for your child.
-Narendra