Fireworks over New "Morning After Pill"?

A Food and Drug Administration advisory panel was slated to meet Thursday to discuss approval of an emergency contraceptive pill, dubbed "Ella," that's already sold in 22 European countries.

"Ella" is expected to prove highly controversial here.

It's designed to prevent pregnancy if taken up to five days after intercourse, two more than "Plan B."

Special Section: Dr. Jennifer Ashton
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On "The Early Show" Thursday, CBS News Medical Correspondent Dr. Jennifer Ashton observed that, "Obviously, there are heavy moral, ethical, social, even financial, political issues with this. We're going to stick to the medical ones, which really, for the most part -- most experts are saying the real big difference between Ella and Plan B is just the duration of time in which they can be used."

One thing raising eyebrows, co-anchor Harry Smith, is the chemical similarity between Ella and the so-called abortion pill, RU-486.

Plan B, Ashton explained, "is made of Levonorgestrel, which is a progesterone-like hormone compound. It can prevent pregnancy up to 72 hours after intercourse ... and it's about 85 percent effective. Ella, or the new one, works up to 120 hours, or five days. (It contains) Ulipristal Acetate, which works to moderate the progesterone effects on ovaries and possibly the uterus."

You don't need a prescription for Plan B in the U.S. If Ella is OK'd, it would only be available with a prescription.

As for Ella's side effects, Ashton says, the most common ones reported include nausea, headaches, abdominal or pelvic pain, menstrual-like pain, fatigue and dizziness -- you're always gonna see those things."

What will the panel and FDA be looking at in considering whether to approve Ella?

"Is it effective," Ashton responded, "does it work in the 120 hours, as it's said to? Is it safe? Obviously, always important. Do there need to be special recommendations for subpopulations, in terms of obese women, and will there be the potential for off-label use? They're going to have to address that."

FDA advisory committees don't have the final word on matters they take up. They're made up of outside experts who make recommendations to the agency, which makes the final decision -- though it usually heeds the advice of the panels.