The use of morning-after pills by American women has more than doubled in recent years, driven largely by rising rates of use among women in their early 20s, according to new federal data released Thursday.
The finding is likely to add to the public debate over rules issued by the Obama administration under the new health care law that require most employers to provide free coverage of birth control, including morning-after pills, to female employees. Some religious institutions and some employers have objected to the requirement and filed lawsuits to block its enforcement.
Morning-after pills, which help prevent pregnancy after sex, were used by 11 percent of sexually active women from 2006 to 2010, the period of the study. That was up from just 4 percent in 2002. Nearly one in four women between the ages of 20 and 24 who had ever had sex have used the pill at some point, the data show.
Morning-after pills are particularly controversial among some conservative groups who contend they can cause abortions by interfering with the implantation of a fertilized egg that the groups regard as a person.
Medical experts say that portrayal is inaccurate, and that studies provide strong evidence that the most commonly used pills do not hinder implantation, but work by delaying or preventing ovulation so that an egg is never fertilized in the first place, or thicken cervical mucus so sperm have trouble moving.
This month, the Obama administration offered a proposal that could expand the number of groups that do not need to provide or pay for birth control coverage. But the proposal did not end the political fight over the issue, which legal experts say may end up in the Supreme Court.
The new data was released by the National Center for Health Statistics and based on interviews with more than 12,000 women from 2006 to 2010. Researchers asked sexually active women if they had ever used emergency contraception, “also known as Plan B, Preven or morning-after pills,” as well as about their use of other forms of birth control.
Over all, 99 percent of sexually active women ages 15 to 44 have used contraception at some point in their lives, or about 53 million women, up slightly from 2002. An earlier report found that 62 percent of all women of reproductive age were currently using some form of birth control.
The new report found that 98.6 percent of sexually active Catholic women had used contraception at some point, but the data did not show how many Catholic women currently use contraception.
Condom use has risen markedly. More than 93 percent of women said they had partners who had used condoms at some point, compared with 82 percent of women in 1995, a likely effect of strong public advocacy for condom use during the AIDS epidemic.
In contrast, women who had used intrauterine devices, or IUDs, at some point in their lives declined to about 8 percent from 10 percent in 1995. The use of birth control pills has remained steady since 1995 at 82 percent.
Eighty-nine percent of white women said they had used birth control pills at some point, compared with 67 percent of Hispanic women, 78 percent of black women and 57 percent of Asian women.
Education played a role in the type of contraception used. Forty percent of women without a high school diploma said they chose sterilization, while just 10 percent of women with a bachelor’s degree said they used that method. Those without a high school diploma were also far more likely to use three-month injectables, like Depo-Provera — 36 percent compared with 13 percent of women with a college degree.
About 12 percent of college graduates said they had used emergency contraception, while 7 percent of women with only a high school degree said they had used it.
Educated women were far more likely to have practiced periodic abstinence based on the menstrual cycle. About 28 percent of women with a master’s degree or higher had practiced this method, while just 13 percent of women without a high school diploma had, the report found.
White women, American-born Hispanic women and black women were most likely to practice withdrawal, with more than half of women in each group saying they have used that method. Just 44 percent of foreign-born Hispanics said they practiced withdrawal.