81mg: I think that the aspirin dose I used. And I used it on my own: may have saved my pregnancy because I learned later that I had a blood mutation! I started it right after I discovered I was pregnant at 17 days after ovulation.
I started taking it before my Dr. told me I could. When I told her I was going to she said it certainly wouldn't harm anything. My RE recently told me the same. So I take it daily, even not pregnant, in hopes of being in your shoes soon! I really don't think it causes any problems, but as with anything, you probably should run it by your Dr. It's actually called low dose asprin as opposed to baby asprin. Not sure what the difference is, but I was told to specifically use the low dose vs. the baby asprin.