Crude rationalization and only describing the second medicine (misoprostol) used - conveniently ignoring the first one.
First, you take a pill called mifepristone. This medicine stops "the pregnancy" from growing (poisons it). Some people feel nauseous or start bleeding after taking mifepristone, but it’s not common. Your doctor or nurse may also give you antibiotics to take to prevent infection.
The second medicine is called misoprostol. You’ll either take the misoprostol right away, or up to 48 hours after you take the first pill — your doctor or nurse will let you know how and when to take it. This medicine causes cramping and bleeding to empty your uterus.
For most people, the cramping and bleeding usually starts 1-4 hours after taking the misoprostol. It’s normal to see large blood clots (up to the size of a lemon) or clumps of tissue when this is happening. It’s kind of like having a really heavy, crampy period, and the process is very similar to an early miscarriage. (If you don’t have any bleeding within 24 hours after taking the second medicine, misoprostol, call your nurse or doctor.)
The cramping and bleeding can last for several hours. Most people finish passing the pregnancy tissue in 4-5 hours, but it may take longer. The cramping and bleeding slows down after the pregnancy tissue comes out. You may have cramping on and off for 1 or 2 more days.
This "sterile" description from your own Planned Parenthood coven.