People deserve to know how contraceptives work, outside of anyone's political agenda. (peteselfchoose, Creative Commons)

As someone who considers herself a contraceptive advocate, I’ve gotten that question dozens of times: from friends, from peers, and especially from students, when I was a pregnancy prevention educator in Los Angeles high schools.

And many of those times, I gave the wrong answer.

For a long time, I was misled—as many people are—about the function of Plan B (the “morning-after pill”) and other emergency contraceptives. I was under the impression that the main difference between Plan B and “regular” birth control was the fact that Plan B prevented implantation—that is, in the event that a sperm fertilized an egg in the aftermath of unprotected sex, hormones from the pill would prevent the fertilized egg from attaching to the lining of the uterus. Without this necessary connection to the woman’s body, the egg would cease to develop or, effectively, “die.”

For those folks who define life as beginning at fertilization, the prevention of implantation, and thus the morning-after pill, constitutes an abortion.

Most recently, this designation of emergency contraception as a form of abortion has led two for-profit corporations—Hobby Lobby and Conestoga Wood Specialties—to bring cases against the Affordable Care Act’s birth control mandate.

“The mandate requires us to become abortion providers,” explained Hobby Lobby President Steve Green. “Our conscience does not allow us to do that.”

Except Plan B, like the vast majority of commonly used emergency contraceptives, isn’t an abortion pill. For one, both common medical practice and federal law define pregnancy as beginning only once the egg has implanted in the uterus. But even more importantly, these contraceptives—contrary to popular belief—don’t actually block implantation, and therefore don’t constitute abortions even if you do believe life begins at the fertilized egg.

Rather, Plan B works by ensuring fertilization never happens in the first place. As Pam Belluck of The New York Times pointed out in her extensive investigative piece on the morning-after pill, sperm from a male and the egg from a female don’t just magically unite right after sex. It takes time for the two to reach other. Often times, they never do—and that’s one of the reasons that every couple who wants to doesn’t get pregnant right away. It is during this window that emergency contraception works, by delaying the release of the egg from the ovaries and by thickening cervical mucus to make it more difficult for sperm to swim.

Not a single study since the 1999 approval of Plan B by the Food and Drug Administration (FDA) has shown that Plan B inhibits implantation. So why all the misinformation? A lot of it can be attributed to the simple repetition of bad science, be it by the media, doctors or informal health educators like myself. Pro-life politicians have capitalized on this error, referring to emergency contraception as “abortive” in public appearances. But the greatest key to this mislabeling mystery is the literal label on the drug, which confirms what science has not: according to the FDA, the drug “may also prevent… attachment of a fertilized egg to the uterus.”

This FDA label has been used in arguments against the morning-after pill by anti-abortion activists, and most recently served as the cornerstone piece of “evidence” brought in the case against the birth control mandate by Hobby Lobby and Conestoga. While the two companies do have a moral basis (though perhaps not a legal one) for objecting the provision of the intrauterine device (IUD), a form of birth control also covered in the mandate that actually does have the potential to prevent implantation, their understanding of the function of Plan B is simply wrong.

More importantly, however, so is the information being represented to the public as medical fact. One of the greatest impediments to safe sex is ignorance. People of all ages and from all backgrounds deserve to be able to make informed decisions about their sexual and reproductive health, and that starts with knowing what a contraceptive drug is actually doing—or not doing—inside their own bodies.

The FDA, however, has effectively stated that they’re not interested in doing anything about the problem. A spokesperson told Daily Beast reporter Tiffany Stanley that companies themselves are typically responsible for initiating the label change process based on new scientific data, a request that is expensive and that the agency has already denied for Teva, the manufacturer of Plan B, once in the past.

But what about scientific data that was never right in the first place? The FDA is willing to self-initiate changes for dosage or other safety concerns: does a gross violation of informed consent, an essential principle of medical practice in the United States, not apply?

No matter what your political agenda is, no matter what the precedent, spreading misinformation about contraceptives only contributes to the body of false knowledge that makes unsafe sex more commonplace and unplanned pregnancy more likely.

In the interest of the folks out there who believe the spread of STDs and the number of children living in poverty in America are due punishment by God, I suppose I can’t say these consequences are objectively, universally bad.

But I think we can go ahead and say they’re opposed to the public interest. I think we can also go ahead and say that misleading the public about a drug is inconsistent with the transparency we should expect from our lawmakers, from our media and from a body charged with protecting and advancing public health. In debates as charged as those around contraception, abortion and the Affordable Care Act, correct information is essential to making appropriate decisions. 

Because anyone who ever might take emergency contraception, has a friend who might or has sex with with someone who might should be able to answer the question: how does Plan B work?