When I first started bleeding with my miscarriage in February, I was obviously worried, and told DH that I was scared. He said it was probably nothing.
The next day at the ultrasound, the doctor hardly said anything while he was searching for any signs of a baby, and when he stepped out so I could re-dress, I was almost in tears and told my husband that I didn't have a good feeling about what the doc was about to say, and my husband said, "Oh, knock it off! Its probably fine."
It made me really mad at the time, but I think it was more that he just didn't know how to handle the situation, so he did is best to console me and himself by trying to convince both of us that everything was just fine.
The bottom line is that it is your body and not his and you know what you're feeling. If you feel that something is wrong, then go in. Tell him that he can either take you in and be supportive about everything, or he can stay home and be an ass, and you'll go anyway, and then he can go live in the doghouse for a while.
Or you could say, "This is your child we're talking about! Why don't you want to do everything possible to make sure that she or he is OK?!"
I know that when my husband gets scared about something, he gets grouchy because he doesn't want to appear "weak" by admitting that he's scared. Maybe that's what's going on.