Is it safe to take 81 mg of baby aspirin while 18 weeks pregnant?

My doctor said it’s safe to take it versus not taking it. I have a gene mutation with 1 copy that makes me a 1-3 risk for a blood clot compare to someone who doesn’t have the gene mutation that I do. It causes DVT. I’am nervous because I didn’t have to with my first pregnancy but this time I might have to. She says it’s a higher risk for a blood clot not taking it versus taking it. Also I have recently been exposed to someone who has Covid.