Let’s increase our use of IUDs and improve contraceptive effectiveness in this country
Robert L. Barbieri, MD (Editorial, August 2012)
In the United States, approximately 49% of pregnancies are reported to be unplanned. From 1995 to 2008 the rate of unintended pregnancy decreased by 42% in Europe, but did not decrease at all in North America.1 One factor contributing to the difference: in Europe, long-acting reversible contraceptives (LARCs) are more widely used than in North America. In the United States, increasing the use of LARCs would cause a decrease in the unplanned pregnancy rate.
In this 2-part editorial, I am focusing on the expanding clinical indications of LARCs, including:
- copper intrauterine device (IUD)
- levonorgestrel-releasing intrauterine system (LNG-IUS)
- etonogestrel-releasing implant (Implanon, which is being transitioned to Nexplanon [see “Completing the Nexplanon training process” on page 10])
- depot medroxyprogesterone acetate (DMPA) injection, which is also a highly effective contraceptive method.
“In last month’s editorial, I focused on the copper IUD and the LNG-IUS.” Here, I am focusing on the etonogestrel-releasing implant and DMPA.
In practice, I observe most clinicians placing the etonogestrel implant from a standing position. One complication of insertion is placing the implant too deeply in the arm (for example, placing the implant in the biceps muscle). You can reduce the potential for this complication by sitting down and directly observing implant placement from the side of the patient’s upper arm, rather by standing above her arm.
The implant and obesity: Effectiveness not defined, but not shown to be ineffective
A 65-in, 250-lb (body mass index, 41.7 kg/m2) woman asks if she can have an etonogestrel implant.
Would you place an etonogestrel implant in this obese woman?
Argument for etonogestrel implant use in obesity. The FDA-approved package insert for the etonogestrel implant states, “The effectiveness of the etonogestrel implant in women who weighed more than 130% of their ideal body weight has not been defined because such women were not studied in clinical trials. Serum concentrations of etonogestrel are inversely related to body weight and decrease with time after implant insertion. It is therefore possible that Nexplanon may be less effective in overweight women, especially in the presence of other factors that decrease serum etonogestrel concentrations such as concomitant use of hepatic enzyme inhibitors.”6 Drugs that induce cytochrome P450 3A4 (CYP3A4) increase the metabolic clearance of etonogestrel. CYP3A4 inducers include barbiturates, phenytoin, topiramate, carbamazepine, and St. John’s wort.
In a large, prospective observational study of 1,168 women who received the etonogestrel implant, only one pregnancy occurred over 1,377 woman-years.7 The pregnancy occurred in a woman with a BMI of 30.7 kg/m2. In this study, the contraceptive failure rate was not significantly different between normal, overweight, and obese women. The cumulative contraceptive failure rate among the obese women was 0.23 per 100 woman-years. By contrast, the contraceptive failure rate among 1,527 women using a contraceptive pill, patch, or vaginal ring was 4.55 per 100 woman-years.8 Based on results from these and other studies, I feel comfortable providing etonogestrel implants to overweight and obese women.
The Implanon device is being transitioned to the Nexplanon device. Nexplanon has an improved insertion system, with a safety needle. Unlike Implanon, Nexplanon can be imaged by standard x-ray because it has barium impregnated in the device.
For providers who have previously completed training for the Implanon device, training for the Nexplanon device can be completed online. You can sign up for the Web-based or the in-person clinical training program through Merck’s Web portal for Nexplanon (http://www.nexplanon-usa.com/en/hcp/services-and-support/request-training/request-form/index.asp).
DMPA is safe immediately postpartum
A 23-year-old G1P1 woman is planning on exclusively breastfeeding her newborn daughter. She has used DMPA successfully in the past and she asks you to prescribe an injection before her hospital discharge.
Would you prescribe DMPA injections to this breastfeeding woman?
Argument for DMPA use immediately postpartum. The FDA-approved product information for DMPA recommends initiating injections 4 to 6 weeks postpartum regardless of the mother’s breastfeeding status. The World Health Organization recommends that DMPA not be initiated prior to 6 weeks postpartum in breastfeeding women. The available research suggests, however, that DMPA is safe to administer immediately postpartum because:9
- DMPA has no significant effect on the development of breastfed infants
- DMPA has a low risk of maternal complications.
The bottom line. Considering the high rate of unintended pregnancy, it is reasonable to prescribe the woman in case 3 an immediate postpartum DMPA injection and schedule her for appropriate postpartum follow-up.