Rush Limbaugh mischaracterized the effects of the emergency contraceptive pill known as Plan B while lecturing listeners on the “cultural decay” caused by the pill's accessibility to teenage girls. Limbaugh repeatedly referred to the pill as an “abortion pill,” describing details of the contraceptive's process that defied reality and displayed a complete misunderstanding of basic female anatomy on the part of the conservative radio host.

On June 10, the Obama administration announced it would drop its insistence on age restrictions for the sale of Plan B, paving the way for consumers of any age to purchase the emergency contraceptive without a prescription.

The next day, Limbaugh addressed a caller who challenged the host's repeated assertions that Plan B caused abortions. Limbaugh initially accepted the caller's accurate assertion that the pill does not terminate pregnancies of any kind, with the caveat that the pill promoted teenage sex and “cultural decay” regardless of this fact.

But after a commercial break, Limbaugh recanted, falsely claiming that the pill does in fact terminate pregnancy, if pregnancy is established at the moment of fertilization rather than at the moment a fertilized egg attaches to the uterine wall.

“Plan B prevents the egg from implanting,” said Limbaugh. “It does not prevent conception.” He continued describing Plan B's interactions, claiming it “delays the release of the fertilized egg to the uterus.”

In fact, emergency contraceptives like Plan B prevent fertilization, not implantation, and in no way terminate pregnancy.

According to a New York Times story on the pill, Plan B works by “delay[ing] ovulation, the release of eggs from ovaries that occurs before eggs are fertilized.” Furthermore, studies have not shown that Plan B is capable of preventing fertilized eggs from implanting in the womb [emphasis added]:

Studies have not established that emergency contraceptive pills prevent fertilized eggs from implanting in the womb, leading scientists say. Rather, the pills delay ovulation, the release of eggs from ovaries that occurs before eggs are fertilized, and some pills also thicken cervical mucus so sperm have trouble swimming.

Not only were Limbaugh's claims about the pill's effects contrary to scientific evidence, his understanding of human biology also appeared to be lacking. While he claimed that eggs are fertilized and then released, with rare exception (ectopic pregnancy), an egg is actually released from the ovary into the fallopian tube and then later fertilized after beginning its descent into the uterus.

Of course, this misunderstanding of basic female anatomy is less than surprising given Limbaugh's demonstrated ignorance of women's issues.