How Morning-After Pills Really Work Religious conservatives are losing one of their primary arguments for trying to ban the morning-after birth control pill that can prevent pregnancy if taken within days after sexual intercourse. They and their political allies have long contended that the pills work by aborting an embryo at the earliest stages of development. But, as Pam Belluck reported in The Times on Wednesday, the latest scientific findings and expert opinion indicate that the pills work by delaying ovulation so that sperm can't fertilize an egg to create an embryo. Belief that the pill might be an abortifacient stems from speculative language that the Food and Drug Administration approved for its original label, which listed a number of physiological processes by which the pill might prevent pregnancy, including preventing fertilized eggs from implanting in the womb. There was no evidence to support that view at the time, and there is none to support it now. Studies in Australia and Chile have convincingly shown that the pill acts solely by delaying ovulation. The F.D.A. now acknowledges that the emerging data suggest the morning-after pill, often called Plan B, does not inhibit implantation. It should remove that unsupported suggestion from the label. Mitt Romney and other politicians need to stop calling it an "abortive" pill. Decisions on whether to take the pill should be left to women. This page supports easy access to the morning-after pill without a doctor's prescription to help prevent unwanted pregnancies. We also support a treatment regimen based on RU-486, which does abort an implanted embryo weeks after the morning-after pill no longer works. It provides a safe alternative to the dwindling availability of surgical abortions in many areas. The decision on taking RU-486 should be left to women and their doctors.