The abortion pill regimen relies on two drugs: mifepristone and misoprostol. Mifepristone is a drug designed to block the pregnancy hormone progesterone, which helps facilitate the flow of nutrients from a mother's body to her unborn child. By blocking this hormone, mifepristone kills an unborn baby through starvation. After the baby has died, the mother will take misoprostol to induce labor and expel the dead child from her body.
APR protocol takes a simple approach to counteract the effects of mifepristone: introducing more progesterone. If a woman changes her mind about continuing her abortion within 72 hours of taking mifepristone, the baby can still be saved. According to the Charlotte Lozier Institute, a doctor can
"prescribe bioidentical progesterone to outnumber and outcompete the mifepristone in order to reverse the effects of the mifepristone. An ultrasound is performed as soon as possible to confirm heart rate, placement, and dating of the pregnancy. The progesterone treatment will usually continue through the first trimester of pregnancy in an attempt to reverse the effects of the mifepristone."
The Lozier report points out that progesterone has been used since the 1950s to reduce the risk of miscarriage and premature birth. It cites two studies (PROMISE and PRISM) demonstrating that progesterone therapy increases the live birth rate and doesn't create safety issues.
