I was quoted on a Fox show. While this is somewhat surprising, the fact that I was put in the same category as Jon Stewart (apparently we are both liberal ideologues) actually left me feeling honored. The issue, of course, is the four methods of birth control that Hobby Lobby is no longer required to cover under their employee health plan due to the recent Supreme Court ruling. Megyn Kelly of Fox apparently took issue with Jon Stewart calling out claims that Plan B is an abortifacient—a drug causing abortion—as “not true” (he is correct) and my statement that “three of the four contraceptives do not lead to abortion, even using the conservative definition of when life begins,” which appeared in The New Republic. Ms. Kelly claims that Plan B and ella (levonorgestrel and ulipristal acetate postcoital contraception, respectively), and Mirena IUS and ParaGard (both intrauterine devices or IUDs), “Can and do end fertilized eggs.” She is wrong.
Unlike my piece or the myriad posts I have written on the subject on my own blog, Ms. Kelly offers no scientific articles to bolster her claims, but rather rests her case on product monographs—basic descriptions of the drugs—and the opinion of the Supreme Court majority. These are five men whose last biology class was likely 40 or more years ago (i.e., before the basic science evaluating these methods of contraception existed) and who do not practice medicine.
Let’s first dispense with the idea that a product monograph should even be considered. Product monographs do not contain the latest research; they are a compilation of FDA labeling requirements and corporate legal lingo used to deflect lawsuits. As more and more data emerges after a product goes to market, monographs become outdated because updating them offers no financial gain. Since I’m a doctor, not a lawyer, I’ll leave the specifics of how the case was argued to lawyers, but if the product monographs of Plan B, ella, Mirena IUS, and ParaGard were used as evidence to support the government’s case, then the government was relying on outdated and inaccurate information.
As a board certified OB/GYN, I’ll stick to what I know. The medicine.
The International Federation of Gynecology and Obstetrics (FIGO) issued a statement in 2008 indicating that a post-fertilization effect for Plan B was not consistent with the mechanism of action and thus should be removed from the product labeling. There is a plethora of medical evidence (this 2013 review article has many excellent references, as does this 2011 FIGO statement) showing no post-fertilization effect on either the embryo or on the endometrium (lining of the uterus). Plan B works by inhibiting a specific hormonal surge that happens before ovulation. It doesn’t work when given on or after the day of ovulation. In one study when Plan B was given after its window of efficacy, the number of pregnancies was exactly what would have been expected had no method been used (i.e., it didn’t work). Were there a lining-of-the-uterus effect, Plan B would be expected to work after ovulation has occurred, but it doesn’t.
What about ella (ulipristal acetate)? The 2012 FIGO Medial and Service Delivery Guidelines on Emergency Contraceptive Pills state the following:
The primary documented mechanism of action for both levonorgestrel and ulipristal regimens is interference with the process of ovulation. … These regimens have been shown not to prevent implantation of a fertilized egg into the uterus in several studies. …
The single 30 mg of ulipristal in ella inhibits ovulation and is insufficient to have an effect on the lining of the uterus. Those who have argued against this claim point to the drug mifepristone (a different medication) and the effects the drug haswhen itis given every day (this is not the regimen for ella)—so both are invalid arguments. What about the fact that ella can delay menses, does that belie a hidden effect on the lining of the uterus? A 30 mg dose of ulipristal acetate delays ovulation so menses may also be delayed. Further evidence for a lack of an effect on the lining of the uterus comes from the fact that subsequent episodes of unprotected intercourse after taking ella reduces its efficacy. When taken in the right reproductive window, ella delays ovulation for five days, allowing the sperm time to die, thus preventing fertilization. However, have sex a second time and the five-day hold on ovulation expires before the sperm. If ella affected the lining of the uterus, we would not see this increased failure rate with subsequent acts of unprotected intercourse. There is no basic science to support a post-fertilization effect, hence the FIGO statement. International organizations dedicated to the health of women don’t make such bold statements lightly.
Kelly claims that the Mirena IUS thins the lining of the uterus, possibly creating an inhospitable environment for an embryo. While the Mirena IUS does affect the lining of the uterus, this is not believed to be its primary mechanism of action. To quote a 2013 study from the journal Contraception, "The major contraceptive action of the levonorgestrel-releasing intrauterine system (LNG-IUS) is cervical mucus thickening." It takes five days for the cervical mucus to be affected, hence why we tell women to use a back-up method of contraception if the device is inserted mid-cycle. The levonorgestrel in Mirena and the inflammatory response may also affect sperm function, although this effect has not been fully elucidated. The effect of Mirena on the lining of the uterus clinically is similar to the effect of long-term use of birth control pills, but if this effect had a contraceptive action missing a few pills each month wouldn’t matter. However, missed pills result in pregnancies all the time.
The only method with a potential post-fertilization effect is the copper IUD, the ParaGard IUD. The copper in the ParaGard IUD causes a profound inflammatory reaction that covers the entire upper reproductive tract and that is toxic to both sperm and eggs. A post-fertilization effect is unlikely in this case, though, because fertilization is unlikely. In the rare cases where fertilization does happen (Copper IUDs do rarely fail and pregnancies do occur), there is no data to support that these fertilized eggs are less likely to implant than fertilized eggs conceived without a copper IUD in place. Further evidence for a lack of effect on the lining of the uterus is the fact that the copper IUD also reduces ectopic pregnancies (pregnancies outside the uterus in the fallopian tube). Experts interviewed by The New York Times also reached the same conclusion. While copper can theoretically damage a fertilized egg, there is no data supporting this as the mechanism of action. When a copper IUD is inserted as post-coital contraception the mechanisms of action are less clear, and a post-fertilization effect cannot be excluded, but most experts (and FIGO) believe even in this scenario it likely works by preventing fertilization. As of 2014, the bulk of the evidence suggests that thecopper IUD when used a standard birth control (i.e., not post coitally) works by preventing fertilization. In fact, with regard to both IUDs, a review article in the peer-reviewed journal Contraception concluded the following:
The common belief that the usual mechanism of action of IUDs in women is destruction of embryos in the uterus is not supported by empirical evidence.
The hypothesis that postcoital contraception and IUDs affect a fertilized egg is an old one that was generated before today’s technology. We now have a mountain of evidence that refutes the idea that Plan B, ella, and Mirena work by ending the “life” of “fertilized eggs.” It’s theoretically possible with ParaGard, but very unlikely. (Never mind that medicine doesn’t consider a fertilized egg a pregnancy). If using the wealth of scientific data (multiple basic science articles, statements of experts in peer-reviewed journals, and international organizations) makes me an ideologue, I’m fine with that. However, I’m not sure that I’d use "liberal" as the label, I think "evidence-based" ideologue is more accurate.