Scientists seeking to dispel the abortifacient impression

Amid a heated national debate over emergency contraception, some scientists are marshaling evidence to challenge the belief that the "morning-after pill" is equivalent to abortion.

Abortion opponents object to the pills, saying they work by preventing implantation of a fertilized egg in the womb and thus destroy an early embryo. Some pharmacists are refusing on moral grounds to dispense emergency contraception.

But the scientists say there is no scientific evidence the pills prevent implantation–and considerable evidence they work mainly by blocking the release of an egg from the woman’s ovary, so no embryo is formed.

"The pervasive myth out there is that emergency contraception is an abortifacient," said Dr. David Archer, director of clinical research at the Contraceptive Research and Development Program of Eastern Virginia Medical School in Norfolk.

"But there’s no evidence scientifically that that’s true."

For one thing, Archer points out, emergency contraception generally doesn’t work if taken after a woman has ovulated.

On the other hand, no one can prove that the pill doesn’t interfere with implantation.