"Plan B May Not Be Effective at a Population Level"

That's the title of a recent article in the OB/GYN News. The article notes how researcher James Trussell has reported at contraceptive technology meeting that a review of 11 studies found there is "no evidence that this increased access (to EC) reduces the number of pregnancies or the number of abortions at a population level."

In an often-cited 1992 paper, Dr. Trussell of Family Health International, Research Triangle Park, N.C., used modeling to suggest that access to emergency contraception could prevent half of all unintended pregnancies and abortions in the United States (Fam. Plann. Perspect. 1992;24:269–73).

But in nine randomized trials and one cohort study in which a total of 11,830 women were enrolled, and in one demonstration project in which 17,831 women were given emergency contraceptive pills (ECPs), not one of the studies found clinically or statistically significant differences between intervention and control groups in pregnancy or abortion......

A third hypothesis is that emergency contraceptive pills have intrinsically low efficacy. The labeling on Plan B (two doses of levonorgestrel) quotes an 89% reduction in pregnancy risk after a single act of coitus, and estimates of risk reduction in the published literature range from 60% to 94%. But Dr. Trussell called all these estimates into question because it's difficult to accurately estimate the expected number of pregnancies that would have occurred without emergency contraception......

Dr. Trussell concluded that the numbers of expected pregnancies reported by studies are probably too high and that most published efficacy figures are probably overestimates. Nevertheless, it's clear that emergency contraceptives produce physiologic effects that are incompatible with pregnancy and that at the very least they are more effective than nothing......

As for how physicians should respond to this new information, Dr. Trussell urged honesty. Physicians should not oversell emergency contraception by implying that Plan B will reduce unintended pregnancy at a population level, he said.

Honesty? Let's hope Trussell hand-delivers that message to Planned Parenthood and Planned Parenthood starts being honest about the effectiveness of emergency contraception. The emergency contraception section of their web site still outlandishly states "EC was responsible for approximately 43 percent of the decrease in the number of abortions from 1994 to 2000" without providing a source.

Tags: emergency contraception, james trussell, planned parenthood