I think it depends how your allergic reaction is. As per my experience as a nurse, if you have mild symptoms(not a systemic one like shortness of breath, rashes, etc) they usually outweigh the risk. Are you allergic to Sulfa drugs too? If you are, get a second opinion. Usually when your allergic to sulfa drugs, your aspirin reaction is pretty much systemic
but the problem is she's allergic.....so that makes it entirely different. I agree, I have heard that it can help in some cases but when you're allergic it seems like it would not be worth the risk. just my opinion. I had a miscarriage, and then 3 months later was pregnant again and delivered a healthy baby girl. I'm now pregnant with #2 and they've already seen the heartbeat.
The reason Dr.s put women on a low dose aspirin (86mg's or lower) is because some women have a clotting disorder where tiny blood clots cut off blood to the baby causing the baby not to get blood causing the m/c. The aspirin acts a blood thinner and keeps the blood from clotting. I had a m/c back in august with my first pregnancy and ever since then I have been taking 1 baby aspirin a day while we are trying and will continue to take one, at least through the 1st trimester and possibly longer. I have not been diagnosed with the blood clotting disorder; however, some research shows that it will help, although they are not sure completely why that is. Some doctors think it won't hurt, so take one! So yes, most doctors believe it is very helpful in preventing m/c's!!
I don't personally think it makes a big enough difference to risk taking a medicine that you're allergic to. Have you had several miscarriages, or only one? You may want to seek a second opinion.