Web edition: May 23, 2012
Print edition: June 30, 2012; Vol.181 #13 (p. 9)
Long-acting birth control devices are nearly 22 times as reliable as contraceptive pills or other short-acting approaches that need close monitoring, a new study shows. Since about half of all unplanned pregnancies are traceable to failed birth control, switching to a long-term, reversible contraceptive could prevent many accidental pregnancies, researchers say.
“As a doctor, if you had a drug for cancer or hypertension that was 20-fold better than the next drug, you would never write [a prescription] for that other drug,” says study coauthor Jeffrey Peipert, a physician and epidemiologist at Washington University in St. Louis. “We hope that clinicians will re-think what is standard practice — that a young woman comes in and gets pills or condom counseling. We have methods that are much, much better.”
The findings also hint that if cost were not an issue, most women given a choice of common hormone-based contraceptives would prefer the long-acting devices. About 77 percent of the women who volunteered for the new study chose an intrauterine device (IUD) or a small implant placed under the skin while only 20 percent requested shorter-acting options such as the pill, a vaginal ring or a skin patch. Fewer still opted for hormone injections called Depo-Provera. All costs were covered by the study. The findings appear in the May 24 New England Journal of Medicine.
“This study brought home how big a difference there is between effective methods and really effective methods” of contraception, and comes at a time when demand for birth control is growing, says Lawrence Finer, a demographer and public health researcher at the Guttmacher Institute and Columbia University in New York City. The point at which women are getting married and giving birth is getting later, he says. “But the age at first sex hasn’t changed that much. You’ve got a long period where people need contraception.”
The researchers monitored 7,486 girls and women who were given the hormonal contraceptive of their choice. (The researchers didn’t offer barrier devices such as condoms or diaphragms.) During three years of follow-up, there were 156 unintended pregnancies that were attributable to some form of contraceptive failure. The pill/patch/ring group had failure rates that ranged from 4.8 percent after the first year to 9.4 percent after the third year, while the long-term devices and injections showed failure rates of less than 1 percent each year.
Teenagers have a lot to gain from long-acting devices, since their record of adhering to daily or on-the-spot birth control is inconsistent, says James Trussell, an economist and public health researcher at Princeton University. “That’s the wonderful thing about these long-acting methods — the implants and IUDs. There are no adherence problems. We call them ‘fit and forget.’”
But misconceptions about contraceptives’ effectiveness remain, he says. “Plenty of researchers have asked people open-ended questions about which contraceptive is more effective,” he says. “A huge fraction get it wrong.”
Peipert says doubts about safety linger as well, in part due to the Dalkon Shield, an IUD from the 1970s that was linked to pelvic infections and pulled from shelves. IUDs no longer have this flaw, but the incident gave them a bad reputation, he says. “Clinicians steered away from giving an IUD to young women or those who hadn’t yet had children. I don’t think that’s a worry anymore. These methods are very safe.”
B. Winner et al. Effectiveness of long-acting reversible contraception. New England Journal of Medicine, Vol. 366, May 24, 2012, p. 1998.
P. Barry. No babies, no hormones: RNA may someday replace 'the pill.’ Science News, Vol.174, July 5, 2008, p. 9. Available online: [Go to]_
A.J. Davis. Intrauterine devices in adolescents. Current Opinion in Pediatrics, Vol. 23, October 2011, p. 557. [Go to]
L.B. Finer and M.R. Zolna. Unintended pregnancy in the United States: incidence and disparities, 2006. Contraception, Vol. 84, November 2011, p. 478. [Go to]