Editor’s Note: The editors present this series (read part 1, part 2, part 3, part 5, part 6) on the recent furor over Plan B as an opportunity for our fellow pro-lifers to slow down, step out of activist mode, and enter into the conversation in a prayerful and thoughtful way.
The Church encourages conversation among faithful scientists and theologians as new science comes to light and as we deepen ethical reflection. Typically such conversations occur in academic settings, but since the recent furor pushed the issue into the open, causing much confusion and scandal, we felt it important to present the latest science and moral reflection in a context of faithful discussion.
We offer this series in a spirit of obedience to the Magisterium, and as an opportunity for faithful Catholics and people of good will to come to a greater understanding of the nuances of the Church’s teaching and the complexities of the science and art of medicine in the difficult situations involving the treatment of women who have been raped. There has been no (and will be no) revision in the Church’s teaching concerning direct abortion or contraceptive sexual acts between spouses. Both are morally illicit without exception.
As with all Truth and Charity Forum articles, opinions belong to the author alone and do not necessarily represent the official position of Human Life International.
In my previous article in this series, I summarized the scientific evidence that suggests that not all morning after pills – in this specific case, levonorgestrel – are abortifacients. In response, my critics have proposed that the numerous studies I cited do not address their specific concerns that Plan B is an abortifacient in a particularly unique way, a proposal that I will call the preovulatory use-postovulatory abortifacient hypothesis.[i]
According to this hypothesis, levonorgestrel can act as interceptive when it is administered during a brief period prior to ovulation before what is called the LH surge (days LH -5 to LH -2). Here, the drug blunts the LH surge that is normally required for ovulation but the blunting of the LH surge is not enough to prevent ovulation. Thus, an egg is released.
However, and this is the crux of the hypothesis, its proponents propose that the blunting of the LH surge would lead to hormonal changes that would detrimentally alter the endometrium preventing, if the egg is fertilized, proper implantation of the embryo. They therefore conclude that LNG is an interceptive and an abortifacient.
There is indeed data that indicates that LNG, when administered after the onset of the LH surge, is often unable to prevent ovulation.[ii] Moreover, it is clear that when ovulation occurs, Plan B does in fact blunt the LH surge.[iii] However, as I have already noted in my published work in the National Catholic Bioethics Quarterly, there is also reliable data that indicates that the blunting of the LH surge by Plan B taken prior to the surge (LH -2), even when ovulation occurs, is NOT accompanied by the hormonal changes that would interfere with endometrial function.[iv]
As Durand et al. (2010) conclude in their study of the effects of LNG ingested two days prior to the LH surge (LH -2): “The apparently normal E2 and P4 production during the luteal phase suggested a normal luteinization and corpus luteum function in LNG-ov cycles [reproductive cycles when LNG administration still leads to ovulation], which agree with the lack of deleterious effects of this hormonal contraceptive regimen on the endometrium.”[v] This finding seriously undermines the tenability of the preovulatory use-postovulatory abortifacient hypothesis, which requires that the blunting of the LH surge leads to hormonal deficiencies that interfere with endometrial receptivity.
It is especially in light of these recent findings that I claim that it is very unlikely that Plan B is an abortifacient in the manner that some have hypothesized: It would be physiologically difficult, if not impossible, for Plan B to impair the endometrium, making it unfit for implantation of an embryo, if it does not alter the post-ovulation hormonal profile of a woman when it is taken prior to the LH surge.
How then do we explain the absence of pregnancies in women who have ovulated despite their ingestion of Plan B?[vi]
One real possibility emerges from the scientific observation that eggs that are released from the ovary when the LH surge is blunted are defective. They are hard to fertilize.[vii]
Whichever explanation we use to account for the absence of these pregnancies, in light of the findings described in the Durand et al. (2010) paper, we have to rule out explanations that involve hormonal disruptions that corrupt endometrial function. In other words, we have to rule out the preovulatory use-postovulatory abortifacient hypothesis.
Next page: Hard for Some to Accept the Science–>