September 20, 2012 — Intrauterine devices and contraceptive implants, with their very low pregnancy rates and high rates of patient satisfaction, are the best method to prevent unintended pregnancy in adolescent girls, according to new guidelines issued by the American College of Obstetricians and Gynecologists.
The latest guidelines, from the Committee on Adolescent Health Care Long-Acting Reversible Contraceptive Working Group, were published in the October issue of in Obstetrics & Gynecology. The guidelines, similar to the 2007 guidelines these replace, bring more data forward.
Long-acting reversible contraception (LARC) such as intrauterine devices (IUDs) and levonorgestrel-releasing intrauterine devices (LNG-IUDs) have lower pregnancy rates than the short-acting birth control methods teenagers are more likely to use, the authors write.
Unintended pregnancy rates for short-acting contraceptives such as condoms, oral contraceptives, contraceptive patches, vaginal rings, and depot medroxyprogesterone acetate (DMPA) injections were 22 times higher than rates for LARC. The pregnancy rate among women using LARC is less than 1% per year. Furthermore, women younger than 21 years who were using short-acting contraceptives were twice as likely to have an unintended pregnancy as older women, according to a study published in May in the New England Journal of Medicine. With LARC, the pregnancy risk was equal for both age groups.
Short-acting contraceptives have far lower continuation rates than LARC methods among teenagers. In a study of 1387 women aged 15 to 24 years using short-acting hormonal birth control methods, few were using the same birth control method a year later. Sixteen percent of those using DMPA injections still relied on them a year later, and 11% of those using the patch remained with that method a year later. The continuation rate was higher for vaginal rings and oral contraceptives, both at 30%.
LARC continuation rates are often well above 70% among teenagers, other studies show. A 2011 study in 4167 girls and women aged 14 to 45 years showed an 86% continuation rate for LARC after 1 year compared with a 55% rate for short-acting contraceptives. Although that study combined data from teenagers and adults, a study that compared LNG-IUD continuation rates for women younger than 20 years with the rates for older women showed similar rates across age groups: 85% of the younger group were using a LNG-IUD a year later, as were 80% of the older women. Copper IUD continuation rates were slightly lower for teenagers than older women, but the 72% continuation rate in teenagers was still far higher than shown in other studies for short-term contraception.
LARC methods are becoming more popular, although they are still in the shadow of short-term birth control. In 2002, 2.4% of women in the United States using contraception relied on a LARC method. By 2009, 8.5% did. Among teenagers aged 15 through 19 years who were using contraceptives, 4.5% use LARC, according to a study published online July 16 in Fertility and Sterility.
"When choosing contraceptive methods, adolescents should be encouraged to consider LARC methods," the authors write. "Intrauterine devices and contraceptive implant are the best reversible methods for preventing unintended pregnancy, rapid repeat pregnancy, and abortion in young women."
The committee report says complications from IUD use are infrequent. Research shows young women using IUDs have no increased risk for pelvic inflammatory disease (PID), nor are they at an increased risk for infertility.
The authors write that complications among IUD users are "rare and differ little between adolescents and older women." Relative risk for PID is increased in the first 20 days after insertion and then returns to baseline, studies show, and absolute risk is low. PID risk with IUD placement is between 0% and 2% when there is no cervical infection, and 0% to 5% when there is an undetected infection. If there is infection, the cause is most likely to be bacterial contamination, and not the IUD itself.
A positive chlamydia test after IUD insertion will not increase the likelihood of PID if it is treated promptly. LNG-IUDs may actually decrease risk by thickening cervical mucus and thinning the endometrium, the authors write.
Women aged 15 to 19 years have the second-highest chlamydia infection rate and the highest rates for gonorrhoea, according to a 2010 surveillance report by the Centers for Disease Control and Prevention, so the report advises testing for sexually transmitted infections, noting that they can be treated with the IUD in place.
"Increasing adolescent access to LARC is a clinical and public health opportunity for obstetrician–gynecologists," the authors write. "With top-tier effectiveness, high rates of satisfaction and continuation, and no need for daily adherence, LARC methods should be first-line recommendations for all women and adolescents."
Obstet Gynecol. 2012;120:983-988. Full text
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