Do intrauterine devices (IUDs) cause infertility in women over 25 years old with no history of hormonal sensitivities or other medical conditions later in life?

Do IUDs Cause Infertility in Women Over 25 Years Old?

No, IUDs do not cause infertility in women over 25 years old. Well-conducted studies demonstrate no increased risk of infertility associated with modern IUD use, regardless of parity status 1.

Evidence Supporting Safety

The U.S. Medical Eligibility Criteria for Contraceptive Use explicitly addresses this concern:

• Data conflict about whether IUD use is associated with infertility among nulliparous women, although well-conducted studies suggest no increased risk 1
• This classification applies to both copper-containing IUDs (Cu-IUD) and levonorgestrel-releasing IUDs (LNG-IUD) 1
• Women aged ≥20 years receive a Category 1 classification for IUD use (no restrictions), indicating the method is safe and appropriate 1

Historical Context and Modern IUDs

The infertility concern stems from outdated data on obsolete devices:

• The Dalkon Shield specifically was associated with increased tubal infertility risk (relative risk 6.8), but this device is no longer available 2
• Older plastic IUDs (Lippes Loop, Saf-T Coil) showed elevated risk (relative risk 3.2) 2
• Modern copper-containing IUDs show minimal to no increased infertility risk (relative risk 1.3 for copper-only users) 2

Mechanism and Return to Fertility

IUDs work primarily by preventing fertilization, not by causing permanent reproductive damage:

• IUDs are highly effective, reversible contraceptive methods 3, 4
• The primary mechanism is prevention of fertilization rather than implantation 3
• Fertility returns promptly after removal in most women 3

Important Caveats

The main risk factor for infertility in IUD users is pelvic inflammatory disease (PID), not the device itself:

• Risk of pelvic infection is slightly elevated only during the first 3 months after insertion (approximately 6 infections per 1000 woman-years) 3
• This risk is primarily related to pre-existing asymptomatic sexually transmitted infections, particularly Chlamydia trachomatis 3
• IUDs do not protect against sexually transmitted infections, which are the actual cause of tubal infertility 3

Clinical Recommendations

For women over 25 considering IUD use:

• IUDs are appropriate first-line contraception with no age-related restrictions for women ≥20 years 1
• Screen for sexually transmitted infections before insertion if risk factors are present 3
• Counsel that IUDs do not cause infertility but also do not protect against STIs that can cause infertility 3
• Both nulliparous and parous women can safely use IUDs without concern for future fertility 1, 4

The only documented fertility concern relates to infection risk from untreated STIs, not from the IUD device itself.