Aspirin to prevent preeclampsia

I had severe preeclampsia in my first pregnancy. This time my doctor has advised me to start taking low dose aspirin to prevent it this time around. However, I also have ulcerative colitis and the aspirin is causing me to go into a flare and bleed. I don’t know to do at his point because neither of these options are good. Is there anything else besides aspirin that I can take for this so it doesn’t mess with my ulcers?