Initial studies of APR have shown it has a 64-68% success rate.
Without the APR treatment, the first abortion pill may fail to abort the pregnancy on its own. In other words, your pregnancy may continue even without APR if you decide not to take the second abortion drug likely prescribed or provided to you. APR has been shown to increase the chances of allowing the pregnancy to continue. However, the outcome of your particular reversal attempt cannot be guaranteed.
No, it is always your choice to change your mind. Even if you have started the chemical abortion process, reversal may still be a choice for you.
Spotting or bleeding is common during the reversal treatment. It is important and safe to continue the progesterone even if you experience spotting or bleeding unless directed otherwise.