VOA标准英语2010年-Stash of Morning-After Pills May Not R（在线收听）

Providing emergency contraception before it's needed does not affect unwanted pregnancy rate

Philip Graitcer | Atlanta, Georgia 22 March 2010

Family planning experts wondered if having emergency contraceptives on hand would prevent unwanted pregnancies.

A new review of 11 medical studies finds that easier access to emergency contraception does not reduce the rates of unintended pregnancy.

Emergency contraceptives, like the so-called morning-after pill, can prevent pregnancy if they are taken within 120 hours of unprotected intercourse. But barriers discourage their widespread and timely use. Some women find it difficult or embarrassing to request a prescription from their doctors or to get the medication in time.

Family planning experts wondered if having emergency contraceptives on hand would solve that problem. Dr. Chelsea Polis, a family planning researcher at the Johns Hopkins University's Bloomberg School of Public Health, explains they gave women the medication as a precaution, so they would have it on hand if they needed to take it.

"Advance provision of emergency contraception is the idea that providing women with a packet or several packets of pills in advance of need will allow them to access the medication more quickly, and that by accessing it more quickly, they'll be able to use it within that recommended time frame," says Polis.

Pill only works if it's taken

She and her colleagues have just completed a review of 11 medical studies that measured the effectiveness of advance provision of emergency contraception.

In the Cochrane Database of Systematic Reviews, she reports, "We found that easier access to emergency contraception did help women use the pills more quickly when it was needed, and they used it more often, but despite that increased use and faster use, it didn't reduce rates of unintended pregnancy."

Polis explains that the strategy did not work as predicted because of what's called a population level effect. "When you can't say for sure whether all the women in the advance provision group actually used the medication, then you're kind of looking at population level effect of a strategy, not the individual effect of a medication." In other words, while emergency contraception is effective for individual women, advance provision can't be expected to make a different in the community.

Because of this finding, Polis says that family planning experts must continue helping women understand when they are at risk of becoming pregnant and teach them how to avoid unintended pregnancy