Rhythm Method: Embryo Killer?

Recently, anti-choice advocate and Christian minister Randy Alcorn mounted a now-familiar argument against the use of the pill as a contraceptive method by suggesting that it amounts to chemical abortion in some cases. “Even an infinitesimally low portion—say, one hundredth of 1%—of 780 million pill cycles per year globally could represent tens of thousands of unborn children lost to this form of chemical abortion.”

In response, Luc Bovens, of the London School of Economics, has written a piece for the British Journal of Medical Ethics positing that the rhythm method causes more embryonic death than contraceptives, as it relies on having sex “on the fringes of the fertile period,” which makes couples “more likely to conceive embryos that are incapable of surviving.”

As many as 50% of conceptions may not survive long enough even to disrupt menstruation, Bovens says. It is reasonable to assume then, he adds, that embryos created from sperm that has been sitting for days within the female's reproductive tract before ovulation may be disadvantaged.

The situation is similar, he suggests, for eggs that have been waiting around for sperm to arrive. These are the only two likely scenarios where fertilisation might occur using the rhythm method, he points out.

These embryos may then face a less-than-ideal uterine lining, he points out, since the uterus is not as receptive outside of the most fertile period.

Bovens calculates that, if the rhythm method is 90% effective, and if conceptions outside the fertile period are about twice as likely to fail as to survive, then “millions of rhythm method cycles per year globally depend for their success on massive embryonic death.”

Bovens’ piece is extremely interesting. You can read the whole thing here (it’s only two pages). My guess is that Alcorn wouldn’t disagree with him; in my experience, Protestants are less likely to advocate the rhythm method than Catholics. Nonetheless, it certainly makes for a clever retort to some oft-heard assertions from the anti-choice crowd, so I thought I’d pass it along. Thoughts?