Baby aspirin safe??

I'm 36 and have conceived fairly quickly in the past. This past year and half has been awful and stumped my doc as to why I wasn't conceiving. In spetemver we finally got pregnant but then lost it in December. After that we went on clomid for 6 cycles and nothing. Now this first cycle after clomid we finally got pregnant. I've had theee miscarriages but not consecutive but since my last was the worst emotionally I am a nervous wreck. I am 5 weeks now and asked my doc what I could do to make sure it sticks and he said I should take 81mg of baby aspirin daily. I was wondering if that would cause spotting since it's a blood thinner? I won't be able to handle spotting again...