Hi doctor, I drank an abortion pill, and started to bleed, I did another test afterwards and it still shows positive, please tell me why?

Half-life of HCG. After an abortion, the HCG levels start to fall. The half-life of HCG is 24-36 hours, so every 24-36 hours the level of HCG in your blood drops by 50%. Pregnancy tests vary in sensitivity to hcg, ranging from 10-100 miu/ml and the level of HCG also varies in pregnancy-e.g., 5 week pregnancy HCG could be 2500-6500. Thus, it may take a few weeks for the pregnancy test to become negative.