My prayers are with your family!  This senerio is very familiar...  We did miscarry (twice actually) and they could never determine why.  I will pray that everything turns out differently for your family. 

Very shortly after the miscarriage I became pregnant with our beautiful son who just turned one.  I had a normal pregnancy with him.  He is SWCAH like his sister and I did take Dex. early in my pregnancy in case of a girl with SWCAH.

Yes, even if we don’t always know why everything happens for a reason.  Be strong and trust in God.