An ultrasound is not required after a pill abortion. While it can sometimes be helpful to confirm the process was successful, it can sometimes also be used to diagnose a woman with an “incomplete abortion” if blood and clot is still seen inside the uterus. This is often a normal finding on ultrasound for a few weeks after using the abortion pills, but it can be used by some health providers to recommend women to have a vaccuum aspiration or a D&C.
Ultrasound should be performed when there is suspicion of complications (heavy bleeding, infection, etc.). However, if the abortion pill process goes as expected without complications, the least invasive method to confirm successful pill abortion is a urine home pregnancy test 4 weeks after using the pills.