Tag Archives: biology

Plan B: Literature Review (Part I)

The mode of action of [emergency contraception, EC] has become he subject of heated debate in North America and in several Latin American and Caribbean countries. The main question is centred on whether or not EC prevents pregnancy by interfering with post-fertilization events. This issue is of importance for many people who consider that a new human life begins at the time that fertilization is completed. Accordingly, interference with post-fertilization events would lead to loss of human life. In spite of a lack of scientific evidence to support a post-fertilization effect, this possibility is used as an argument to turn legal, political and religious constituencies against the availability and use of EC. (Ortiz, et al, 2004)

In order to satisfy my own curiosity and my critics, I’ve reviewed recent scientific literature related to the question of whether or or not Plan B is abortifacient. I do not wish to appear to be in any way “rooting” for Plan B and/or its supporters. I am not. However, I have been very frustrated by the way that many of my fellow pro-lifers have repeatedly stated confidently that Plan B sometimes acts after fertilization and is therefore abortifacient. I do not believe such confidence is supported by scientific evidence. The goal of this literature review is to present a fair appraisal of the likelihood of postfertilization effects caused by Plan B to the pro-life community.

For the most part my analysis will proceed in chronological order, but I’ll begin with a newer article (Croxatto, Ortiz, and Müller, 2001) that provides an brief primer on the relevant reproduction science. Continue reading

Plan B: Preview of Literature Review

In order to satisfay my own curiousity and my critics , I've begun a review scientific literature related to the question of whether or or not Plan B is abortifacient . Here are the articles currently on my reading list. Feel free to suggest others.

  1. Croxatto HB, Devoto L, Durand M, Ezcurra E, Larrea F, Nagle C, Ortiz ME, Vantman D, Vega M, von Hertzen H. Mechanism of action of hormonal preparations used for emergency contraception: a review of the literature. Contraception 2001;63(3):111-121.
  2. Durand M, del Carmen Cravioto M, Raymond EG, Duran-Sanchez O, De la Luz Cruz-Hinojosa M, Castell-Rodriguez A, Schiavon R, Larrea F. On the mechanisms of action of short-term levonorgestrel administration in emergency contraception. Contraception 2001;64(4):227-234.
  3. Kahlenborn C, Stanford JB, Larimore WL. Postfertilization effect of hormonal emergency contraception. Ann Pharmacother 2002;36(3):465-470.
  4. Croxatto HB, Ortiz ME, Muller AL. Mechanisms of action of emergency contraception. Steroids 2003;68(10-13):1095-1098.
  5. Muller AL, Llados CM, Croxatto HB. Postcoital treatment with levonorgestrel does not disrupt postfertilization events in the rat. Contraception 2003;67(5):415-419.
  6. Croxatto HB, Brache V, Pavez M, Cochon L, Forcelledo ML, Alvarez F, Massai R, Faundes A, Salvatierra AM. Pituitary-ovarian function following the standard levonorgestrel emergency contraceptive dose or a single 0.75-mg dose given on the days preceding ovulation. Contraception 2004;70(6):442-450.
  7. Gemzell-Danielsson K, Marions L. Mechanisms of action of mifepristone and levonorgestrel when used for emergency contraception. Hum Reprod Update 2004;10(4):341-348.
  8. Ortiz ME, Ortiz RE, Fuentes MA, Parraguez VH, Croxatto HB. Post-coital administration of levonorgestrel does not interfere with post-fertilization events in the new-world monkey Cebus apella. Hum Reprod 2004;19(6):1352-1356.
  9. McGregor JA, Equiles O. Risks of mifepristone abortion in context. Contraception 2005;72(5):393-393.
  10. Mikolajczyk RT, Stanford JB. A new method for estimating the effectiveness of emergency contraception that accounts for variation in timing of ovulation and previous cycle length. Fertility and Sterility 2005;83(6):1764-1770.
  11. Pruitt SL, Mullen PD. Response to letters to the editor regarding Contraception or Abortion? Inaccurate Descriptions of Emergency Contraception in Newspaper Articles, 1992-2002. Contraception 2005;72(5):396-397.
  12. Pruitt SL, Mullen PD. Contraception or abortion? Inaccurate descriptions of emergency contraception in newspaper articles, 1992-2002. Contraception 2005;71(1):14-21.
  13. Spinnato II JA, Mikolajczyk R. Emergency contraception — a different interpretation. Contraception 2005;72(5):395-395.
  14. Stanford JB, Larimore WL. Description of Emergency Contraception in the Media. Contraception 2005;72(5):394-395.
  15. Trussell J, Jordan B. Mechanism of action of emergency contraceptive pills. Contraception 2006;74(2):87-89.

A Spectral Smack-Down

Arlen Specter reamed out Advanced Cell Technologies scientist Rober Lanza for their hype about having found a way to non-lethally harvest embryonic stem cells. As you may have heard, this development was only theoretical, as all of the embryos were destroyed so all their cells could be harvested and the chances of getting viable embryonic stem cells would be optimized. And since the success rate was two percent, "optimized" is very relative. We therefore cannot say that we have a non-lethal (let alone non-harmful) method of harvesting human embryonic stem cells (hESCs).

At first, ACT was only guilty of hype, which it has done before, but now folks on the web are calling out Lanza for having left out some critical details: when the AJOB blog, which is very pro-embryonic research, has an entry called "Paging Dr. Hwang?", you know something juicy came out.

What folks now say is that ACT soaked the harvested cells (blastomeres, to be precise) in the same dish as the original embryo, providing some cellular signals that would help the harvested cells live and be viable embryonic stem cells. This doesn't nullify the ultimate premise of their research, but it's black eye for Nature and a further disgrace to ACT. Perhaps ACT wanted this technique for themselves, and while they wanted the hype of a Nature article, they didn't want competitors replicating those results.

 (HT: Wesley Smith, who has posted half a dozen entries on this topic. You'd be well-served to read his and AJOB Blog's many fine points about this issue, particularly AJOB's entry on the "Kevorkianization of Stem Cell Research"–I'll even forgiven them for conflating all stem cell research with embryonic stem cell research…this time. 😉 )

Plan B: Not Abortifacient But Not a Panacea Either

When Karina at Netscape.com linked to yesterday's post about Plan B, she lumped me in with those whose "buzz on this ruling is overwhelmingly positive". While I do not believe that Plan B is abortifacient, and therefore needn't be fought by pro-lifers as such, that does not mean that I think over-the-counter access to it is a good idea.

First of all, it's only going to worsen the already pervasive and pandemic contraceptive mentality in this country. However, that alone would be unsufficient grounds for banning Plan B or restricting access to it. If our opposition to Plan B is really based on its contribution to the culture of licentiousness, we'd be lobbying for condoms, the Pill, and various other prevalent forms of contraception, which I think we'd find difficult to justify or achieve in our pluralistic society. If we wish to counter the contraceptive mentality, we need to do so through leading by example. "They will know we are Christians by our love." That love should be so abundant and effusive that those outside of and weaker members within the Body of Christ should marvel at it and weep at its absense in their lives. Furthermore, that love should be so superabundant that in order to be fully expressed and nurtured it must become flesh and be born as our beloved children.

Getting back to the matter at hand, I would certainly not classify my reaction to wide availability to Plan B as "overwhelmingly positive". Nor would I characterize my sympathizers' reactions as such. I do not rejoice in the popular pursuit of sexual pleasure and gratification as ends unto themselves, divorced from their proper place in sacramental marriage. However, my primary discomfort with OTC availability of Plan B has more do with medicine and Hippocratic concerns than sexual morality.

"[M]ake a habit of two things – to help, or at least to do no harm." I'm not certain it won't do harm, especially if its administration cannot be monitored by health professionals. The birth control pill, aka the Pill, of which Plan B is a very large dose, requires a prescription. Providing Plan B over-the-counter seems an odd decision in that light. Also, offering it OTC to those over 18 while requiring prescriptions for minors seems unpracticable. If it's really important to restrict minors' access to the drug, there should be more concern that adults will purchase it OTC and give it to minors. Most serious, though, is how little is known about the long-term effects of taking Plan B once, let alone multiple doses. I worry that Plan B will become a frequent and commonplace fail-safe for when primary means of contraception fail or are not used – either carelessly or deliberately – rather than a rarely used emergency remedy. We just don't know what repeated use would do to a woman's health, and that worries me. I pray that Plan B doesn't kill people like RU-486 has.

In sum, while I do not believe Plan B is a form of chemical abortion that should be fought by the Culture of Life, I am certainly not overjoyed by the prospect of it being available without prescription.

Investigating NFP: The Great Embryo Killer? (Update)

Some updates regarding Bovens' bunkum:

The NY Times printed a reasonably fair article about the paper – a welcome contrast to many articles that proceded it .

Bovens has responded to his critics. I'd intended to fisk his inadequate responses, but others have already done that far better than I ever could.