Nelson · Expert opinion on drug delivery 2017 · narrative review · n=?

LNG-IUS 12: a 19.5 levonorgestrel-releasing intrauterine system for prevention of pregnancy for up to five years.

Cited 23 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Narrative review and expert opinion with no primary data or systematic search methodology

PubMed 28696796 · doi:10.1080/17425247.2017.1353972 · record verified 2026-08-26

What was done

This narrative review summarizes clinical data across approximately 60,000 cycles of use to describe the contraceptive efficacy, safety, and tolerability of the 19.5 mg levonorgestrel-releasing intrauterine system (LNG-IUS 12), as well as the potential influence of age, parity, and body mass index on outcomes.

What was found

The abstract reports no numerical efficacy rates, failure rates, or adverse event frequencies. It qualitatively describes LNG-IUS 12 as offering 5-year contraceptive protection with a smaller frame, narrower inserter, and lower rates of amenorrhea compared to higher-dose systems.

Why it matters

LNG-IUS 12 expands contraceptive options by combining a 5-year duration of use with a smaller frame and lower amenorrhea rates for individuals who prefer a mid-dose hormonal device.

Limits

As an expert narrative review rather than a systematic review or primary trial, the abstract provides no specific numerical data, Pearl indices, or exact participant counts, relying instead on high-level qualitative summaries.

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