Pam Belluck’s outstanding story on the science of the morning after pill and the politics of its labelling sits at the nexus of investigative and science reporting and embodies the best of both traditions:

But an examination by The New York Times has found that the federally approved labels and medical Web sites do not reflect what the science shows. 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.

It turns out that the politically charged debate over morning-after pills and abortion, a divisive issue in this election year, is probably rooted in outdated or incorrect scientific guesses about how the pills work. Because they block creation of fertilized eggs, they would not meet abortion opponents’ definition of abortion-inducing drugs. In contrast, RU-486, a medication prescribed for terminating pregnancies, destroys implanted embryos. [NYT]

Back in October, I reviewed the research on the workings of the morning after pill to settle an argument with some friends. I came to the same conclusions as Belluck. A body of elegant in vitro and in vivo experiments in tissues, animals, and humans show that the morning after pill (aka high-dose birth control) works like birth control, namely, by preventing ovulation.

One minor quibble: Belluck frames the story as part of the abortion debate, which is certainly how the anti-choice faction is approaching the issue. But even if emergency contraception did prevent implantation, EC would be no more an abortifacient than an IUD, a popular form of birth control that does prevent implantation. According to medicine, and common sense, abortion presupposes pregnancy, and pregnancy presupposes implantation. If you’re not pregnant, it’s not an abortion. But once again, anti-choicers are trying to redefine medical terminology for partisan ends.

At a time when science journalists are pressured to hedge, defer to authority, and give equal time to opposing sides regardless of their intellectual merit, Belluck bucked the trend, assessed the evidence, and stated her conclusion for the record.

Then Belluck went on to hold powerful institutions accountable by asking pointed questions. If the science says that the morning after pill is birth control, why do government-approved labels and health information resources raise the specter that the emergency contraception is an abortifacient? As you might expect, conservative pressure groups like the anti-choice Family Research Council are very interested in FDA labelling because these descriptors shape medical and policy conversations. Belluck reviewed the records on FDA approval for emergency contraception and found that the caveat about preventing implantation was grandfathered in from earlier labelling discussions about birth control pills. There is some question about whether daily birth control pills might discourage implantation by thinning the lining of the uterus. This conjecture remains unproven for regular birth control, but follow-up studies have shown the question to be a moot point for emergency contraception. One large dose of hormones doesn’t have time to alter the lining of the uterus the way daily birth control pills do.

The labels were written in a period of genuine uncertainty. Today, the scientific consensus is clear, but anti-choice groups are campaigning to keep the misleading labels intact. With any luck Belluck’s outstanding reporting will spur citizens to demand that scientific accuracy prevail over ideology.

[Photo credit: Grasshopperkm, Creative Commons.]