Does the return of bleeding with a Mirena (levonorgestrel-releasing intrauterine device (IUD)) around 6 years after insertion in a female of reproductive age signal that its effectiveness is waning?

Return of Bleeding with Mirena at 6 Years: Does It Signal Waning Effectiveness?

No, the return of bleeding around 6 years does not signal that the Mirena is losing contraceptive effectiveness—the device remains highly effective for up to 7-8 years with a cumulative failure rate of only 0.68% during years 6-8. 1, 2

Contraceptive Efficacy Remains Intact

• The Mirena IUD maintains its contraceptive protection well beyond the FDA-approved 5 years, with documented effectiveness extending to 7-8 years 1, 2
• The failure rate during years 6-8 of use is extremely low at 0.68%, comparable to the failure rate during the initial years of use 1, 2
• Bleeding pattern changes do not correlate with contraceptive failure—the mechanism of contraception (thickening cervical mucus and inhibiting sperm motility) remains independent of bleeding patterns 1

Why Bleeding Patterns Change Over Time

The return of bleeding after years of amenorrhea or light bleeding is related to declining local progestin levels affecting the endometrium, not contraceptive failure:

• The Mirena releases 20 micrograms of levonorgestrel per 24 hours initially, but this rate gradually decreases over time 1
• As local hormone levels decline, the endometrium may become less suppressed, leading to breakthrough bleeding or return of menstrual bleeding 3
• This represents a shift in the endometrial response to lower progestin levels, not device malfunction 4

What to Evaluate When Bleeding Returns

If bleeding returns or changes after years of stable patterns, consider underlying gynecological problems before attributing it to the device alone: 4, 5

• Device displacement or expulsion—perform a speculum exam to visualize strings and consider ultrasound if strings are not visible 4, 5
• Pregnancy—although extremely unlikely (0.68% failure rate), rule out if clinically indicated 4, 1
• New pathologic uterine conditions—polyps, fibroids, or endometrial pathology that may have developed independently 4, 5
• Sexually transmitted infections—cervicitis can cause irregular bleeding 4, 5

Clinical Management Algorithm

1. Confirm device position: Check for visible strings; if absent, obtain pelvic ultrasound 4

2. Rule out pregnancy: Urine pregnancy test if any clinical suspicion 4, 5

3. Evaluate for pathology: Consider pelvic exam, STI screening, and pelvic ultrasound to assess for structural abnormalities if bleeding is heavy, prolonged, or concerning 4, 5

4. Provide reassurance: If device is properly positioned and no pathology is found, counsel that bleeding changes are common and do not indicate contraceptive failure 4, 1

5. Offer symptomatic management: NSAIDs for 5-7 days during bleeding episodes if the patient requests intervention 4, 5

6. Discuss options: If bleeding is unacceptable despite reassurance, counsel about either early removal and alternative contraception, or continuing use with the understanding that contraceptive protection remains intact 4, 1

Key Counseling Points

• The device does not need to be removed at 5 years—it remains effective for contraception through year 7-8 1, 2
• Bleeding pattern changes are expected as the device ages but do not compromise contraceptive efficacy 1, 6
• Women who use consecutive Mirena devices (replacing at 5 years) typically experience minimal irregular bleeding with the second device, as the endometrium is already adapted to progestin exposure 6, 7
• Approximately 70% of women using a second consecutive Mirena remain free of bleeding during years 2-5, with up to 49% experiencing amenorrhea 6

Common Pitfall to Avoid

Do not automatically remove the Mirena at 5 years or when bleeding patterns change—this leads to unnecessary device removal in women with continued contraceptive protection and often results in gaps in contraception or use of less effective methods 1, 2. The device should only be removed if pathology is identified, the patient finds bleeding unacceptable despite counseling, or the device has reached 7-8 years of use 4, 1.