A news story out today contends that when a woman uses an Intrauterine Device (IUD) for birth control this “is associated with a 40% reduction in the risk of endometrial cancer.”
Yet, do not be deceived by this alluring headline. The news stories (and the physician quoted) fail to tell you two very important facts:
1) This 40% “relative risk reduction” means that the absolute risk of this very rare cancer will fall from 1 case per 13,333 women to 0.6 cases per 13,333 women per year. In other words, it would take 22,222 women to use the IUD to result in 1 less case of this cancer per year. Whopee!
2) However, there would be many more unborn children lost (or killed) by the IUD.
My bet is that most women, who believe invaluable human life begins at conception, would not want to take this IUD risk.

One expert has said, “It is important for the patient to understand that the IUD does not appear to be an abortifacient but, rather, prevents conception.”
You can read my original response to this false assertion in the American Family Physician journal.
One point that I make is that a systematic review of the mechanisms of action of the IUD, published in the American Journal of Obstetrics and Gynecology, the author, Dr. Spinnato, wrote, “Several important conclusions can be drawn from the available literature regarding the mechanism of action in IUDs:

(1) “The available evidence supports a continued significant role for a postfertilization (abortifacient) mechanism of action of IUDs.

(2) “There is little compelling evidence to suggest that . . . IUDs reliably eliminate the likelihood of fertilization.”

Dr. Spinnato concluded, “the analysis of the evidence strongly suggests that the contraceptive effectiveness of [IUDs] is achieved by both a prefertilization spermicidal action and a postfertilization inhibition of uterine implantation.”
A more recent review, by my good friend, Joe Stanford, M.D., concluded, “although prefertilization effects are more prominent for the copper IUD, both prefertilization and postfertilization mechanisms of action contribute significantly to the effectiveness of all types of intrauterine devices.”
For those who believe life begins at conception or fertilization, then a “postfertilization inhibition of uterine implantation” would be an abortifacient effect.
Therefore, for these women, the significant chance of ending the life of their pre-born child can in no way be balanced by an extremely small risk reduction in a very uncommon cancer.