lots of studies are retrospective and many prospective studies unfortunately don’t address libido or sexual functioning formally with questionnaires, especially at baseline. There are also lots of confounders, for example a big one is starting or switching a new contraception is often associated with relationship changes. Could some women feel sexually coerced into giving up condoms? Might others decide to get the IUD because things seem to be working out and then they stop working out. Are these issues due to the contraceptive or perhaps was it just the relationship drug haze wearing off? There are studies looking at how the lust of a new relationship affects the brain and it turns out new love lights up the same areas of the brain on functional MRI as opioids and the effect can last for nine months. Yes, in the first few months of dating you are basically high on the person. So when sexual interest wanes is it the loss of the high and reality setting in or is it the IUD? Causation or correlation?
This is exactly why a copper IUD arm is so important in studies that look at contraceptive side effects because it can serve as the right kind of control. Using condoms as a control doesn’t work because there may be something different about a coupleship that relies on condoms vs one that relies on a woman using long acting reversible contraception.
Which brings me back to this great new study that addresses the impact of the levonorgestrel IUS (Mirena), the copper IUD, and the contraceptive implant on sexual functioning. The study is prospective and the women were screened for sexual functioning at baseline and again at 3 months after initiating their method. They also asked the women about bleeding and about how confident they felt about being in control over whether they got pregnant with their method of choice. The study was carried out at Planned Parenthood of Utah.
195 women were enrolled and 159 completed the three-month follow-up (drop-outs in studies are common and taken into consideration during enrollment). The breakdown of the choice of contraceptive was as follows:
- 46% Mirena
- 20% Copper IUD
- 34% implant
Here is the outcome at 3 months:
At three months 40% of women reported positive changes in their sex lives, 43% reported no change and 17% reported negative changes. Interestingly, 88% of women who reported their method had worsened their sex life worse reported increased vaginal bleeding while only 38% of women reporting sexual improvements reported increased vaginal bleeding.
More women who reported positive sexual changes had a higher degree of perceived control over getting pregnant, meaning taking the worry about pregnancy off the table may be a factor in the role of highly effective birth control in improving sexual functioning. Women who reported negative sexual changes reported being less satisfied with their ability to “let go” during sex.
This is only short-term data, but it supports the information that is already out there. Hormone levels are highest at the beginning with both implants and the Mirena so if there were truly a hormone impact one would have though the Mirena and implant would have fared much worse than the copper IUD.
Most women will not have a worsening of sexual function with either IUD or with the implant and those who do are more likely to be having irregular bleeding. That may come in handy when discussing sexual side effects as bleeding issue tend to improve over time with the Mirena and the implant or may be useful when considering a contraceptive switch.
Just more good news about LARC.