As a Catholic theologian, I am aware that the Catholic Church tends to be so promotional of NFP as to neglect to inform users that, as in all medical advice, there are potentially dangerous “side effects” to the use of NFP. This practice is unfortunate. It destroys confidence and subverts “honesty in advertising.”
Consider, for example, the medical advice given to patients by The American College of Obstetricians and Gynecologists:
Q. How effective is NFP in preventing pregnancy?
A. Natural family planning is not as effective as most other methods of birth control. One in four women who use this method become pregnant. The method is not suited for the following women:
• Women who should not get pregnant because of medical reasons
• Women with irregular menstrual periods who may not be able to tell when they are fertile
• Women with abnormal bleeding, vaginitis, or cervicitis (these make the cervical mucus method unreliable)
• Women who use certain medications (for instance, antibiotics, thyroid medications, and antihistamines) that may change the nature of vaginal secretions, making mucus signs impossible to read
• Women with certain problems unrelated to fertility (for instance, fever) that can cause changes in basal body temperature (source)
If our bishops would include these on a “warning label” with their NFP promotional pitches, then Catholic women who suffered through unwanted pregnancies would feel relieved that it was not their fault that they got pregnant while using NFP. Meanwhile, those considering using NFP for the first time would be encouraged to know that the bishops are straight shooters and that they are not blinded by ideological and theological factors.
As things now stand, the glowing testimonials in favor of NFP are motivated by the “unspoken truth” that NFP is currently the ONLY OFFICIALLY APPROVED method for regulating pregnancies. Hence,
Catholics who want to believe that Paul VI could make no major error in drafting Humanae Vitae will want to do fancy cartwheels to demonstrate that he was 100% right about NFP.
Consider this, for example. When you visit the cheerful site known as Catholic Online, you will hear a Catholic mother of six explaining how she came to hold fast to NFP. Along the way, however, she makes some pretty fantastical claims:
When women learn to read their cycles, they often report a renewed sense of self-worth. . . . Women often can’t place their finger on it, but they sense this. Not surprisingly, couples who practice a method of NFP have only a 5% rate of divorce by comparison to the 50% rate in the population at large. Clearly, when couples treat one another with dignity and respect, honoring the wholeness of each person, their relationship is positively effected.
I say “fantastical” because if the text in red were true, then sex therapist and couples counselors would have used this info by way of shoring up sagging marriages everywhere–and not just among Catholics. Yet, if it seems too good to be true, it probably is not true. And this unfortunately is the case, despite the fact that I have heard this claim routinely used in NFP promotionals. Hence, this is something like being told to take huge doses of vitamin C to prevent the onset of the common cold. “Every belief works in the eyes of the believer” (Michael Polanyi).
Mark Twain — ‘What gets us into trouble is not what we don’t know. It’s what we know for sure that just ain’t so.’