Have you talked to a doc about whether firearms are actually dangerous?
I've known pregnant women that have competed in matches. It's a special sort of humbling to get smoked by a pregnant woman. Anyway, they all said they checked with the doc first and it was OK.
Good thoughts
First, no freaking way am I mentioning guns to my doctor. Most docs are anti-gun and most obstetricians are anti-homebirth. My dr does not yet know that there is no way I'm gonna show up at the hospital to have this kid. The combination of being a crazy gun-owner plus a crazy home-birther plus well, crazy could easily result in a CPS call. That is a whole kind of trouble I don't want to deal with. Also, I generally prefer more detailed research to asking a doctor who may give a good, well-reseached answer, or who may take a guess, sometimes not a particularly good one.
Second, I do know of pregnant women who shoot. I also know of a pregnant woman (a foaf) who shot a fairly large bear at six months pregnant. But I also know that loud noises cause hearing loss, that the damage is incremental, and that although fluid and tissue can dampen the sounds, there are many, many variables at play. Although virtually all babies receive hearing screenings at birth, those do not detect mild or some moderate hearing loss. After that, it is perfectly possible and likely for in-utero hearing loss to go undetected for years and eventually be attributed to some other cause. In short, I think that hearing loss is probable with target shooting, although I would be comfortable with just a few shots, as when hunting, and I do not trust anecdotal claims that "I did it and it never hurt my kids". No disrespect to anyone intended, I am ok with things in pregnancy that many women aren't, but target shooting at normal volumes with normal ammo is not one of them. I wish it was, but I just can't look at the facts and be comfortable with it.