The trouble with implants

Few things in life come with such a great success rate: 99.5%. Almost perfect. The etonogestrel implant, trade name Implanon or Nexplanon, has just that. It's failure rate is a mere 0.05%. That means that if you have an implant, you are virtually guaranteed not to get pregnant for the three years while it's in place. It's a little soft plastic rod that a doctor slips into the underside of your upper arm, and with a little lidocaine, the whole procedure is quick and not too painful. 

With such great statistics, why doesn't every woman desiring contraception book an appointment with her OBGYN and just slip one in there?! In two words: side effects. Of women who have the implant, somewhere between 53% and 90% will have it removed within 2 years. The complaint we hear most often is that it causes bothersome bleeding- spotting, irregular periods, unexpected episodes that crop up at all the wrong times. In one clinical trial, 11.3% of women had their implant removed because of bothersome bleeding.

Dr. Guiahi and her colleagues at the University of Colorado Anschutz Medical Center noticed this problem in their patients and came up with a novel solution. What if we give women with implants who are complaining of bothersome bleeding a short, fourteen day course of hormonal oral birth control pills to even things out? Perhaps this will stop the bleeding and reset their system? Most irregular bleeding in this scenario is due to endometrial atrophy due to the effects of the progestin in the implant. Endometrial atrophy causes irregular shedding of the uterine lining and thus irregular bleeding. Estrogen opposes the progestin effects on the uterine lining and should theoretically fix the problem.

They designed a double blind randomized controlled trial, and 32 women with an implant complaining of bothersome bleeding were enrolled. Half received a fourteen day course of combined OCPs and half received an identical-looking placebo pill. The bleeding stopped for 87.5% of the women taking the OCP and for only 37.5% of the women taking the placebo pill. This means that women taking the OCP were 11.7 times more likely to experience resolution of their symptoms. Great news!

Here's the kicker. Did it last? Unfortunately, the answer is no. For women on OCPS whose bleeding stopped while taking the pills, the bleeding restarted in a mere 5.5 days (median). 85.7% of the women taking OCPs experienced bleeding recurrence in 10 days or less after stopping the pills. There has been prior research looking at other combinations of oral hormonal pills, but, just as in this case, none provided long term relief.

Ultimately, this problem remains unresolved. Implants offer women exceptional birth control with a great safety profile and overall, high satisfaction rates. We have yet to find a way to cope with the most bothersome side effect: irregular bleeding.