I have actually never heard about "health issues" before just b/c of having a child with another person that is a different race than you. Of course, family history plays a part...........
I am of a mixed race - Caucasian and Korean - no health issues here with myself or my brother, or my nieces and nephews who are also mixed.
I wouldn't worry at all - just eat healthy and stay active and take your pre-natals! And if anyone gives you any negatives comments about having an interracial child, completely ignore them and remember how beautiful your child will be - getting the best of both worlds, so to speak!
Anyone who said something to me about that issue would be very sorry they opened their mouth!!!!
Congrats and good luck....I hope you have a wonderful pregnancy!