Aspirin intake during pregnancy

HI, I'm 19 wks pregnant,and 43 yrs old with my 1st baby.I'm currently in Qatar,the Dr here prescribed me Aspirin 100 mg per day although I'm not diabetic,obese, nor hypertensive. He told that hr had prescribed me Aspirin because of my age(late pregnancy).I'm am in doubt of taking aspirin.I'm currently taking natal fish oil,Obimin,calcium and iron.Can somebody enligthen me whetet I should take Aspirin or not.Thanks so much