Washington ? Emergency contraception — the morning-after pill — should be available without a prescription, on pharmacy shelves next to the aspirin and cough medicine, government advisers said Tuesday.

The nation’s largest gynecology group had urged the move, saying it would greatly increase women’s ability to get the pills in time to prevent pregnancy: within 72 hours of rape, contraceptive failure or just not using birth control.

Used widely, emergency contraception could cut in half the nation’s 3 million unintended pregnancies each year, and in turn prevent hundreds of thousands of abortions, proponents told scientific advisers to the Food and Drug Administration.

“There is a public health imperative to increase access to emergency contraception,” said Dr. Vivian Dickerson, president-elect of the American College of Obstetricians and Gynecologists.

The FDA’s advisers agreed, on a 23-4 vote, that the Plan B morning-after pill should be sold over the counter. A key consideration, they cautioned, would be clearer wording on the package so that women understand:

l Use it as soon as possible after unprotected sex. Although it’s highly effective for 72 hours — cutting a woman’s chance of getting pregnant by up to 89 percent — it works best in the first 24 hours.

l Like other hormonal contraceptives, it does not protect against sexually transmitted diseases.

l It is a backup contraceptive, and should not be used instead of routine birth control.

Cost could deter some women from using emergency contraception too regularly. Each one-time-use pack today costs $20 to $30, about as much as a month’s worth of regular birth control pills. It’s not clear if the over-the-counter price would change.

Manufacturer Barr Laboratories promised a massive consumer education campaign, including a 24-hour hot line for advice on using the drug.

The FDA isn’t bound by its advisers’ recommendations but usually follows them.

Commissioner Mark McClellan said Tuesday that the FDA would make a final decision on the morning-after pill in “a matter of months.”

Asked whether political considerations would be taken into account, McClellan said, “We have a lot of information coming in. It’s very much a science-based process.”

Morning-after pills have been sold by prescription in this country since 1998 under the brand names Plan B and Preven. Makers sought to sell only Plan B over the counter.

Used by millions

The FDA says emergency contraception is safe, having been used by millions of women here and abroad with few side effects. The question for nonprescription use, the agency says, is whether women will understand how and when to use it without professional advice.

FDA’s advisers were persuaded by a study of 585 women that found more than 90 percent correctly took the first dose of Plan B in time after reading the box. A second dose is supposed to be taken 12 hours later, and 73 percent took that dose on schedule. Most others were a few hours off, although several of FDA’s advisers said that shouldn’t lessen the effectiveness.

Some advisers wanted restrictions on teen access to nonprescription Plan B, arguing that there wasn’t enough study of the drug in minors. Also, “I’m concerned there will be an exploitation of young women’s fears about becoming pregnant,” and thus they’ll use it more than necessary, said adviser Dr. Susan Crockett, a Texas gynecologist who opposed the nonprescription switch.

The FDA responded that there were no age restrictions on prescription Plan B, and it couldn’t enforce any on an over-the-counter version. Other advisers said teenagers in particular should avoid pregnancy.

To improve access, five states already allow women to buy the morning-after pill directly from certain pharmacists without a prescription, so-called “behind the counter” sales. Those states are: Washington, California, Alaska, Hawaii and New Mexico.

The FDA should not require pharmacists to dispense Plan B, most advisers agreed.

Morality questions raised

Morning-after pills are higher doses of the hormones in regular birth control pills. If a woman already is pregnant, they have no effect. They work by preventing ovulation or fertilization, and possibly by interfering with implantation of a fertilized egg into the uterus, the medical definition of pregnancy.

Consequently, emergency contraception hasn’t proved nearly as controversial as RU-486, the abortion pill.

It does have critics who oppose any interference with a fertilized egg, and the debate drew dozens of proponents and critics into sometimes angry discussion Tuesday that occasionally veered into the morality of contraception.

Women who use emergency contraception show an “inability to control themselves in sexual situations,” said Jennifer Taylor of the anti-abortion Human Life International.

Other critics bemoaned teenage access to emergency contraception, and argued that broader access for everyone might discourage routine birth control.

Proponents argue there’s no evidence that access to emergency contraception makes women more careless about regular birth control.

“Please do not insult our intelligence or belittle us,” said Linda Freeman, who told of desperately calling New York City clinics before one agreed to phone in a prescription for her without a $150 doctor visit that she couldn’t afford. “We must be allowed to make reproductive decisions for ourselves.”