By Mary Brophy Marcus

HealthDay Reporter

TUESDAY, Aug. 6 (HealthDay News) -- Withdrawal is an old-fashioned, unreliable form of birth control, but one-third of young women still use it anyway, new research indicates.

"Our study showed that use of withdrawal for contraception is very common, but it doesn't work as well as other methods," said study author Dr. Annie Dude, a resident in the department of obstetrics and gynecology at Duke University Medical Center, in Durham, N.C.

Dude and her colleagues analyzed 2006-2008 data from a national survey of U.S. women, focusing on 2,220 participants between the ages of 15 and 24. Their aim was to see how commonplace it was for young, sexually active women to use withdrawal as a way to avoid pregnancy.

The findings will be published in the September issue of Obstetrics & Gynecology.

The investigators found that 31 percent of the women used withdrawal as a form of birth control at least once. Of those who used it, about 21 percent became pregnant unintentionally compared with only 13 percent of women who used other types of contraceptives.

Withdrawal users were also 7.5 percent more likely to have used emergency contraception (such as Plan B or Next Choice).

Women who relied on the withdrawal method, which depends upon a man "pulling out" (hopefully) before ejaculating, as their only form of birth control, tended to be less likely to get pregnant than women who used withdrawal along with other forms of birth control over the course of the study, but Dude said this finding was not statistically significant.

She said the research shows that health care providers who care for sexually active young women need to recognize that one reason couples may use withdrawal as a method of birth control is that they haven't planned ahead, and that providers need to take the time to discuss more effective birth control methods with their patients.

"My overall take is that doctors think this is such an antiquated method of birth control that they don't really think to address it with their patients," Dude said.

One expert who wasn't involved with the study said the reasons that might lead a woman to choose the withdrawal method over something more reliable are complicated.

"Many contraceptives are short-acting and require a lot of action on the part of a woman. Using a condom, having a condom, going to the store or pharmacy to get one. Refilling the pill, taking it every day, getting a prescription refilled. Travel and moving. So many issues make these contraceptive methods difficult to use or to be consistent about," said Dr. Kari Braaten, an obstetrician-gynecologist at Brigham and Women's Hospital, in Boston.

Another expert called the study "nicely done" and said it had important findings.

Dr. Angela Chen, an associate clinical professor of obstetrics and gynecology at University of California, Los Angeles, and the family planning division chief at Ronald Reagan UCLA Medical Center, said it's not at all surprising that people who are using this method have more unintended pregnancies. For the withdrawal method to work successfully, she said both partners need to be highly motivated.

"You need couples who've been together a long time and can communicate well," Chen said. "The woman really needs to understand her menstrual cycles -- when she is most fertile -- and most women do not. Their perceptions are all over the place. An app for fertility tracking can be a good start. Bring your menstrual calendar to your provider to learn more."

She added that the results also suggest that practitioners need to talk about Plan B with their patients more openly. "We should be able to recommend it to anybody on a short-acting contraceptive; anyone who might have a method failure should be offered Plan B."

Study author Dude said the most effective contraception for this age group is a long-acting, reversible method such as an intrauterine device (IUD), or a contraceptive insert in the arm.

But obtaining more effective contraception options -- from long-acting methods to Plan B -- can be difficult for younger women, said Braaten at Brigham and Women's.

"There are certainly issues of access for the age group in this study -- young women ages 15 to 24," Braaten said. "I'd like to stress that one of the things we need to do is improve access to long-acting methods like IUDs and implants, so we minimize these experiences and encounters where women find themselves needing to rely on an 'emergency' form of contraception like withdrawal or Plan B when they're otherwise unprepared."

More information

The U.S. Office on Women's Health has more about birth control.