"This is great news [because] the need for emergency contraception is so great," Streicher said, pointing out that 50 percent of pregnancies are unplanned. Among those, she said, half involve couples using contraceptives that either malfunctioned -- like a condom breaking -- or were insufficient, like a diaphragm used without spermicidal foam.
"People often think unplanned pregnancies are [the consequence of] people being irresponsible, but that's not [usually] the case. It's often from a failed attempt at contraception -- that's why it's so important that we have emergency contraception."
Streicher says the longer window for taking ellaOne fills a much-needed gap in reproductive health because those who most often have unwanted pregnancies -- teenagers and those without access to adequate gynelogical care -- cannot always get to a doctor for treatment within a day or two.
While teens 17 and older can get Plan B over-the-counter, those under 17 would need to see a doctor, and it is these girls that may be most affected by a three-day time limit on the existing emergency contraceptive pills, Streicher says.
"In a perfect world you want anyone to use emergency contraception within 24 hours, but the reality is that having this five-day option is going to decrease the number of undesired pregnancies," she said.
But this more powerful form of emergency contraception raises several concerns for anti-abortion rights advocates.
Harrison said that unlike Plan B, ellaOne is chemically similar to the common abortion pill RU-486, which is taken to abort a fetus as late as two months into pregnancy.
She believes that ellaOne is likely to carry the same risks as RU-486, such as excessive bleeding and infection, and said her biggest concern is the often overlooked risks this new drug could pose to the women who take it.
Harrison cites one study of Plan B, currently available over-the-counter, in which more than half the women who participated didn't know how to use the pill correctly. Incorrect use can lead in a failure of the drug and/or adverse side effects.
Harrison fears that if ellaOne were to be brought to the states as another over-the-counter option, the chance for misuse and adverse side effects would be high.
If the FDA approves ellaOne for use in the states, however, it will be given only through a doctor, not over-the-counter.What's more, in a recent study on the drug, the only serious adverse event researchers found with ellaOne was dizziness, and this only occurred in one subject.
Another concern among pro-life critics of the drug is the fear that it will give women a sense of false security, leading them to be more lax about using contraception or practicing abstinence.
"Habits follow technology. Contraception was supposed to prevent an abortion, but it has led to an increase in abortion when people got used to it being around. The increased effectiveness of technology [like this] means people will relax that much more on their inhibitions," said Stephen Phelan, communications manager for Human Life International, an anti-abortion missionary organization.
But Streicher countered that in her twenty years of experience, and in the literature on the topic, this fear is unfounded.
"Emergency contraception does not increase the chance that someone is going to not use contraception or that someone is going to start sexual activity at an earlier age. On the contrary, it is necessary option for women who have that rare contraception failure or...even more importantly, for those who are raped."