(Reuters Health) – Up to 17 percent of young adults in the U.S. may be using “withdrawal” to prevent pregnancy, although not necessarily relying just on that method, a new study finds.

In the sample population of 15-24 year olds, men and women who feared condoms would interfere with pleasure and women who said they would be “pleased” by an unplanned pregnancy were two to four times more likely than others to have used withdrawal.

“The condom and pleasure variable didn't surprise me, it's intuitive, it makes sense, but I think the strength of its association surprised me,” said study coauthor Jenny Higgins, a public health researcher at the University of Wisconsin, Madison.

She added that scientists don't often ask about pleasure in research on contraception and condoms but when they do, they learn a lot more about who is using certain methods and why.

Withdrawal or “pulling out” is not considered to be an effective form of birth control on its own and is not recognized by the Centers for Disease Control and Prevention as a contraceptive method, although Planned Parenthood says it can work effectively up to 96 percent of the time if done correctly every time.

“I think that withdrawal as a method is much less effective than many great methods, like IUDs for example, so I would never recommend that young persons only use withdrawal,” Higgins said.

But withdrawal could be a great option as a backup or additional method, she said, and that’s how many of the young adults in the study reported using it.

For their study, published in the journal Contraception, Higgins and her coauthor used national survey data for 2006-2010. They analyzed responses from a total of 1,607 young men and 1,849 young women, most in their 20s, who were sexually active, not pregnant or trying to get pregnant, and not infertile or sterile.

Participants were asked what types of contraceptives they had used the last time they had sex before the survey. About 14 percent of participants said they’d used withdrawal with additional contraceptive methods, and 7 percent said they only used withdrawal.

About 70 percent of the women and almost 60 percent of men said they would be upset if the woman got pregnant. But among those women who said they’d be pleased by a pregnancy, 13 percent used withdrawal, compared to 6 percent of women who would not be pleased.

Just over 60 percent of women said using a condom wouldn’t reduce their physical pleasure while just over 30 percent of men said the same.

For both women and men, those who felt that condoms were likely to diminish sexual pleasure were more than twice as likely to have used withdrawal with or without other methods.

Among men and women who used withdrawal, the majority did so in conjunction with other methods, sometimes up to a total of three, the researchers note.

About 65 percent of men and women reported use of withdrawal along with an IUD or hormonal contraceptive such as birth control pills or implants. Less than a third used just a condom plus withdrawal or withdrawal alone.

The study team also analyzed socioeconomic factors, including age, race, religion, personal and family education levels, health insurance status and receipt of public assistance. None of these correlated with the likelihood of using the withdrawal method.

Richard de Visser, a senior lecturer in psychology at the University of Sussex in the UK, said these findings are somewhat disappointing because they suggest that many young people are not acting to protect themselves properly against the risk of unplanned pregnancy or sexually transmitted infections.

“It is perhaps not surprising that people who were less concerned about unplanned pregnancy were more likely to report use of withdrawal,” de Visser told Reuters Health by email.

De Visser, who was not involved in the study, said “many people have negative attitudes toward condoms - some will not use them at all, opting instead for less reliable methods such as withdrawal.”

These findings suggest that many people have misperceptions about the efficacy of withdrawal that should be addressed, he added.

“In addition to looking at withdrawal we also need to do more to encourage correct use of condoms - that means putting them on before any genital contact and not removing them early - and to improve attitudes toward condom use,” he said.

Higgins, pointing to the majority of withdrawal users who used an additional method, cautioned, “we need to be careful before we malign withdrawal users – these could be extremely motivated young people who are doing this on top of other things.”

Younger adults use condoms more frequently than any other age group, Higgins added. “I feel like there's this tendency to say that young people are really bad about this stuff, but they can be better than most older adults,” she said. “I feel they are doing things in some ways better than we're giving them credit for.”