Clinical scenario: Which IUD is it?

Can you tell what IUD this patient is using without removing it?

Yes, but you’ll need to visualize the strings and may need access to ultrasound.

There are currently five IUDs available in the US—one copper IUD (Paragard) and four levonorgestrel (LNG) IUDs (Liletta, Mirena, Kyleena, and Skyla). Patients make decisions about what IUD to use based on a variety of factors, including preferences for a hormonal or non-hormonal IUD, effects on bleeding patterns, anticipated duration of use, as well as what IUDs are available. Since an IUD can be used for years and patients may change providers or lose information given to them on the day of placement, patients are often uncertain about the type of IUD they have. If a patient isn’t sure which IUD they have, there are a few ways to identify which type of IUD someone has without removal.

Can you tell what IUD it is without a pelvic exam?

While you may not be able to determine exactly what IUD someone has without a pelvic exam, questions about menses prior to IUD insertion and changes to bleeding patterns since IUD insertion can help to identify if someone has a non-hormonal, copper IUD or an LNG IUD. An increase in menstrual duration, flow, and cramping without changes to timing of menses would be more likely for patients with a non-hormonal, copper IUD, while unscheduled, lighter, and irregular bleeding patterns or amenorrhea would be more likely for someone with an LNG IUD. Additionally, LNG IUDs with higher doses of LNG are more likely to cause amenorrhea with around 20% of Mirena and Liletta users, 12% of Kyleena users, and 6% of Skyla users having no periods after one year of use.

How will a speculum exam help?

The IUDs currently available in the US each use one of three color strings, a.k.a. removal threads. Visualizing string color during speculum exam* can help narrow down which IUD a patient is using. If the strings are white, then the IUD is a non-hormonal, copper IUD (Paragard). If the strings are blue, then the IUD is an LNG IUD, either Liletta or Kyleena. If the strings are brown, then the IUD is an LNG IUD, either Mirena or Skyla. Hence, while visualizing the strings can confirm if someone is using a copper IUD, it only narrows down the possibilities for LNG IUD users.

Back to the case study–on speculum exam, you are able to visualize the strings and they are blue. Which IUD does she have?

Since the IUD strings are blue on speculum exam, she is using either a Kyleena or Liletta IUD. 

How can you know if it’s a Kyleena or Liletta IUD?

In this scenario, to know for sure which IUD they are using, you will need a transvaginal ultrasound to visualize the IUD. If a silver ring is visualized by ultrasound and the strings are blue, then the IUD is Kyleena. If a silver ring is visualized by ultrasound and the strings are brown, then the IUD is Skyla.

On ultrasound exam, the IUD does NOT have a silver ring. You now know that she is using a Liletta IUD.

Since she had her IUD placed three years ago and you were able to determine that it is a Liletta IUD, which is effective for eight years, she can confidently continue using her IUD without the need for removal today.

What if you cannot see the strings on pelvic exam?

If you are not able to visualize the IUD strings, you may need to confirm intrauterine placement with ultrasound and may not be able to identify the IUD type. For more information about IUD removal when strings are not visible, you can review this educational video from ACOG, created for providers.

Key Points 

• Patients may not know their IUD type, especially if it was placed years ago or at a different clinic. Bleeding patterns and string color can offer helpful clues.
  
• A pelvic exam can help identify the IUD type by visualizing the color of the strings:
  • White = Paragard (copper)
  • Blue = Liletta or Kyleena
  • Brown = Mirena or Skyla
• Ultrasound can confirm the specific LNG IUD.
  • Kyleena and Skyla have a visible silver ring.
  • Liletta and Mirena do not have a visible silver ring.