How a medical abortion works.
Some forms of birth control stop fertilization.
Some forms stop the implantation of a newly fertilized egg.
Some forms expel an implanted fertilized egg.
The distinctions are becoming important as a legal and practical matter.
I am not a doctor and I have never experienced menstruation. I write a political blog, not a medical one. I have "done my research" in the way a hundred million Americans did their research about COVID vaccinations. That means I consulted sources that seem credible to me. The graphics below come from Scientific American, which has an explanation I could follow. Their information was consistent with other sources I consider credible, like those from Planned Parenthood. Here is a link.
Everyone old enough to read this blog knows the basic facts. Barriers like condoms and diaphragms stop sperm from meeting egg: No fertilization means no pregnancy. Hormonal birth control stop ovulation: No egg means no fertilization means no pregnancy. It gets complicated with IUDs because depending on the material in the IUD it may stop implantation of a fertilized egg. However, if the IUD is made of copper, it may mostly work by killing sperm and therefore stopping fertilization, although it also stops implantation of a fertilized egg if the copper didn't kill all the sperm. Some states may allow copper IUDs but outlaw ones made of other material.
There is also an over-the-counter drug called "Emergency Contraception" or "Plan B." This does not cause an abortion although it is sometimes confused for doing so. The name implies that it is a problem pregnancy. No. It is used after contraceptive failure. The drug stops ovulation for that month. No ovulation, no fertilization, no pregnancy.
Some ways of stopping pregnancy openly acknowledge that a pregnancy is being stopped and an implanted fertilized egg is to be expelled. This is the "Medical Abortion" protocol. In 2016 the FDA approved a two-drug combination of Mifeprex and Cytotec to be taken within seven weeks from the start of a woman's last period. Mifeprex (also called RU-486 or mifepristone) can work on its own, but the two-drug combination is shown to be about 99.6% effective in large trials.
Medical abortions are at risk of being banned in states that define abortion as acts that stop the natural development of a fertilized egg. Oklahoma's governor is preparing to sign a bill banning all abortions after fertilization. It uses a Texas-style enforcement mechanism through private lawsuits, and therefore does not need to wait for the Supreme Court to overrule Roe v. Wade. Oklahoma's law may become the pattern. It makes the distinction between "Plan B" emergency contraception pill and the "medical abortion" pills. Plan B is allowed. Medical abortions are not. Plan B stops ovulation. Medical abortions expel an embryo.
Who needs to know this stuff? Voters do. These distinctions will be at the center of the national debate over abortion.