#308 Can It Stay or Must It Go? Extended Use of Intrauterine Devices
CLINICAL QUESTION
How effective and safe are levonorgestrel and copper-T380A intrauterine devices for preventing pregnancy beyond the recommended durations of use?
BOTTOM LINE
If it is not possible or desirable to replace a levonorgestrel 52mg or copper-T380A intrauterine device (IUD) at the end of the approved duration of use, small observational studies demonstrated similar efficacy and safety for up to two additional years, with little evidence afterwards. Guidelines suggest that with patient-informed discussion, deferral of IUD replacement for up to twelve months is reasonable.
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EVIDENCE
- One systematic review:1
- Levonorgestrel (LNG) IUD 52 mg (Mirena™): 4 cohort studies, 2089 participants:
- Health Canada approved duration: 5 years.2
- Years 6 & 7:
- 0.02 pregnancies per 100 person-years (95% CI 0–0.29).
- Expulsion and infection rates: ~0-3%.
- Bleeding/pain leading to discontinuation 0.2 to 6.2%.
- No data on devices with other levonorgestrel dosages.
- Copper-T380A IUD: 2 cohort studies, 473 participants:
- Health Canada approved duration: 10 years.3
- Years 11 & 12:
- No pregnancies reported (95% CI 0–0.8 pregnancies per 100 person-years).
- Expulsion rate ~1%.
- No infections or perforations (reported in one study).
- Bleeding/pain leading to discontinuation 1-5%.
- An earlier systematic review4 found similar results.
- Levonorgestrel (LNG) IUD 52 mg (Mirena™): 4 cohort studies, 2089 participants:
- Limitations:
- No randomized controlled trials were identified. Evidence presented is from relatively small observational studies.
- Most studies were in parous participants.
- Statements from the Society of Obstetricians and Gynecologists of Canada (SOGC) and the American College of Obstetricians and Gynecologists (ACOG) are consistent with these findings.5,6
- SOGC: “Intrauterine contraception (IUC) may be safely continued beyond its approved duration of use.” Removal or replacement may be deferred for up to 12 months.
- ACOG: “Data indicate that the copper IUD, [and] the LNG-20 IUD… are all effective beyond their FDA-approved durations of use.”
- Average annual rates during first five (LNG) or ten (copper-T380A) years of use7:
- Pregnancy: ~0.1% (LNG), ~0.4% (copper-T380A).
- Expulsion and infection rates: ~0.06-1% (LNG), ~0.02-1.5% (copper-T380A).
- Discontinuation due to bleeding or pain: ~7% (LNG), ~3% (copper-T380A).
- IUD cost is ~$350 (LNG 52mg) or ~$78 (copper-T380A).8
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some replacement deferral is reasonable
interesting
informative
iud’s are effective beyond their expiatory date.
helps patient informd conversations
“Average annual rates during first five (LNG) years of use7:
Pregnancy: ~0.1% (LNG)” that ‘s one pregnancy for every 1000 woman (or 10 for every 10,000 women) using for one year.
Compare that with what is cited earlier: ” Years 6 & 7:
0.02 pregnancies per 100 person-year ” which is 0.2 pregnancies per 1000 woman using per year (or 2 /10,000).
So my question is why is LNG seemingly more efficacious during years 6-7 than during 1-5 ?