A.H.
I went to a game seven months pregnant and it was totally fine. Just plan on going, don't cancel just because you're pregnant unless you have serious issues. Baseball games are relaxed, you can get up anytime to go to the bathroom or get food, or get some shade. Maybe try to think of a friend that would be able to go with him on the off chance that you couldn't make it for some reason, like you're not feeling so great that day. Guys definitely love going to games with their friends, and he'd still appreciate the gift.