In December advisers to the Food and Drug Administration recommended that a “morning-after pill,” previously available only by prescription, be made available to U.S. consumers over the counter. The pill, marketed as “Preven” and “Plan B,” is not the same as RU-486, the “abortion pill” that terminates development of a fertilized egg in the uterus. The morning-after pill is essentially a concentrated dose of the progestin and estrogen found in birth-control pills. Taken no more than 72 hours after intercourse (24 hours is best), the pills are 89 percent effective in preventing pregnancy.
The morning-after pills delay ovulation and interfere with fertilization. They may also prevent a fertilized egg from being implanted in the uterine wall. In some people’s eyes, this last effect constitutes abortion—so for hard-line foes of all abortion, the pills are objectionable.