A Modest Proposal: Rethinking the Rythm Method

Luc Bovens, a philosophy professor at the London School of Economics has published an interesting paper on reproductive ethics in this month’s Journal of Medical Ethics. The paper titled “The Rhythm Method and Embryonic Death” asserts that the rhythm method of contraception, which is the only contraceptive method prescribed by the Catholic church, is actually responsible for far more embryonic deaths than either the oral contraceptive or condoms. His paper begins with the statement:

“Some proponents of the pro-life movement argue against morning after pills, IUDs, and contraceptive pills on grounds of a concern for causing embryonic death. What has gone unnoticed, however, is that the pro-life line of argumentation can be extended to the rhythm method of contraception as well. Given certain plausible empirical assumptions, they rhythm method may well be responsible for a much higher number of embryonic deaths than some other contraceptive techniques.”

Professor Bovens argument hinges on understanding the rhythm method’s success as being due to not one, but two actions on possible conception.

First, the rhythm method allows partners to avoid sexual intercourse at the time in a woman’s cycle when she is most likely to conceive (what Bovens calls the “heightened fertility period” and what other natural family planning methods call the “fertile window”). By giving women a way to chart their cycle, and figure out when this window is, they can avoid conception by avoiding the possibility of sperm and egg being in the same place at the same time (give or take 6-8 days).

But Bovens points to a secondary mechanism of the rhythm method, which is that just prior to, and immediately following a woman’s “heightened fertility period” an embryo (if created) is least viable, and the uterus is least hospitable to an embryo. Thus, if intercourse occurs, and an embryo was to be formed, it is at a time when it would be least likely to survive.

According to his calculations (which are well thought out, but openly based on assumptions that are impossible to confirm) two to three embryos will have died every time the rhythm method results in a pregnancy. He compares this with one embryonic death for every pregnancy occurring with condom use.

If reducing embryonic death is really the rasion d’etre of the “pro-life” movement Bovens asserts that they must come down against the rhythm method as well:

“…clearly it is callous to use a technique that makes embryonic death likely by organizing one’s sex life so that conceived ova lack resilience and will face a uterine wall that is inhospitable to implantation.”

While the argument is an interesting one, and offered, I imagine, with some degree of seriousness, the inevitable absurdity of the kinds of distinctions required to make this argument are not at all lost on Professor Bovens who end his paper suggesting that,

“one could simply conceive of this whole argument as a reductio ad absurdum of the cornerstone of the argument of the pro-life movement, namely that deaths of early embryos are a matter of grave concern.”

Personally I’m worried that people will take this argument to heart and the next thing you know the government will refuse to fund programs that discuss the rhythm method, and the Catholic church will take that one option away.

Reference: The rhythm method and embryonic death. L. J. Bovens. Journal of Medical Ethics 32: 355-356.

Read more - New Scientist: Rhythm method criticised as a killer of embryos