Do you need to have an ultrasound after doing an abortion with pills?

If you do not have symptoms of a complication, it is not necessary to have an ultrasound after a medical abortion.

By having an ultrasound you can determine whether the pregnancy has ended even a few days after the abortion, especially if you are unsure whether the abortion was successful. You can also have a home urine pregnancy test about 3-4 weeks after taking the medicines. If you take the home urine pregnancy test before waiting 3 weeks, it can show a false result that a woman is pregnant, because there are still pregnancy hormones in her body.

Medical abortion, like miscarriage, is a process that takes place over time and the body might take several weeks to fully expel all the tissues and products in the uterus. This is normal. If you want, you can have an ultrasound about 10 days after taking the medicine just to confirm as soon as possible that the pregnancy has ended.
Even if the pregnancy has ended, many women will still have tissues and blood inside the uterus for several weeks. If you do not have any symptoms of complications like strong pain in the belly, continuous fever, very strong bleeding, smelling vaginal discharge, there is no need for any surgical intervention, like vacuum aspiration, even if the doctors suggest this. One can wait until after the next menstruation or take 2 tablets of misoprostol under the tongue.

More scientific information:

The research has shown that for an accurate diagnosis of incomplete abortion, the ultrasound has to be interpreted together with a clinical examination (signs of complications like excessive bleeding, severe and prolonged pain, fever and/or abnormal vaginal discharge), because the ultrasound results after medical abortion are very similar in complicated and uncomplicated abortions. 69
The surgical evacuation of the uterus (through curettage/ vacuum aspiration) in a clinically well woman is not indicated even if some remains of the abortion can be seen on ultrasound exam. Waiting until the next menstruation, as is done in the case of miscarriage, is often sufficient for all cases, except for ongoing pregnancies. 70
Research shows that one week after the medical abortion up to 77% of women with uncomplicated first-trimester medical abortions still had some remaining tissue and blood in the uterus. 71
Overall only 3% of all first-trimester medical abortions complicate due to retained products of conception (incomplete abortion). Even if the results of the ultrasound show endometrial thickness or increased volume of the uterus this doesn’t mean there is a complication or need for medical intervention. 72