What is a contraindication and how do you know if you have one?

Contraindications are conditions or situations might keep you from being able to safely use Mifepristone-Misoprostol. These are generally things that you will already know about yourself.
Screening you for these contraindications on the internet is very similar to the screening process at a face-to-face visit between a doctor and a patient. The doctor generally finds out about contraindications by asking the patient if she has any of these medical conditions.
You might not know whether or not you are allergic to one of the medicines, but allergic reactions to these medicines are uncommon (0,008%) and very mild (hives).

More scientific information:

Women usually know if they have an IUD, hemorrhagic disorders, or chronic adrenal failure; if they are undergoing long-term corticosteroid therapy; or if they have an allergy to mifepristone, misoprostol, or another type of prostaglandin.7 A woman might not know whether or not she is allergic to one of the drugs, but allergic reactions to these drugs are uncommon. In a study that accounted for 80,000 women who have used Mifepristone-Misoprostol, 6 women (0.008%) had mild allergic reactions (hives) after they took mifepristone.15 In these 6 cases, the women developed hives, or welts on the skin that are extremely itchy. All of the women received treatment with an oral antihistamine and took the misoprostol with no further problems.15

“All contraindications to Mifepristone-Misoprostol, aside from gestational age…are uncommon and based on medical history and therefore should already be known to women. Indeed, doctors screen women mainly by asking them if they have the conditions 7 ."