Copper IUD vs. Hormonal IUD for Emergency Contraception

observational-study PMID: 33503342

Quick Summary: Researchers compared the effectiveness of the copper IUD (a non-hormonal option) and a hormonal IUD (containing levonorgestrel) as emergency contraception. They found both were highly effective at preventing pregnancy after unprotected sex.

Copper IUD vs. Hormonal IUD: What the Study Found

This study looked at two types of IUDs used as emergency contraception:

Copper IUD: This IUD doesn't use hormones.

Hormonal IUD (levonorgestrel): This IUD releases a small amount of the hormone levonorgestrel.

The study found that both IUDs were very effective at preventing pregnancy when inserted within 5 days of unprotected sex. The hormonal IUD was just as effective as the copper IUD.

Study Details

Who was studied: Women in Utah who needed emergency contraception after having unprotected sex.

How long: Researchers checked for pregnancy one month after the IUD was inserted.

What they took: Women were randomly given either a copper IUD or a hormonal IUD (levonorgestrel).

What This Means For You

Choice of Emergency Contraception: If you need emergency contraception, both the copper IUD and the hormonal IUD are good options.

Long-Term Contraception: If you want long-term birth control, the hormonal IUD offers the added benefit of potentially lighter periods.

Talk to Your Doctor: Discuss your options with your doctor to decide which IUD is best for you. They can help you consider your medical history and preferences.

Study Limitations

Location: The study was only done in Utah, so the results might not be exactly the same for everyone.

Short Follow-Up: The study only looked at pregnancy rates for one month.

Small Numbers: Because both IUDs are very effective, there weren't many pregnancies in the study, which makes it harder to see small differences between the two.

Key Findings

The study found that the levonorgestrel 52-mg intrauterine device (IUD) was noninferior to the copper T380A IUD for emergency contraception (EC). Pregnancy rates were 0.3% (1/317) in the levonorgestrel group and 0% (0/321) in the copper IUD group at 1 month post-insertion. The absolute difference of 0.3 percentage points (95% CI: -0.9 to 1.8) fell within the prespecified noninferiority margin of 2.5 percentage points. Adverse events were comparable between groups (5.2% vs. 4.9).

Study Design

This was a randomized noninferiority trial with a double-blind design (participants unaware of group assignments). Conducted at six clinics in Utah, it included 711 women seeking EC after unprotected intercourse within 5 days prior to presentation. Participants were randomized 1:1 to receive either levonorgestrel IUD (n=355) or copper IUD (n=356). The primary outcome was pregnancy status at 1 month, assessed via urine tests, surveys, or health records.

Dosage & Administration

The levonorgestrel IUD (52-mg) and copper T380A IUD were administered via uterine insertion within 5 days of unprotected intercourse. Both groups received standard counseling and follow-up at 1 month. The study focused on IUD placement as EC, not oral copper supplementation.

Results & Efficacy

Pregnancy rates:
Levonorgestrel IUD: 1/317 (0.3%; 95% CI: 0.01–1.7).
Copper IUD: 0/321 (0%; 95% CI: 0–1.1).
Noninferiority: The between-group difference of 0.3 percentage points (95% CI: -0.9 to 1.8) confirmed levonorgestrel IUD noninferiority.
Adverse events: 5.2% (levonorgestrel) vs. 4.9% (copper) sought medical care within 1 month (not statistically significant).

Limitations

Geographic specificity: Conducted in Utah, limiting generalizability to other populations.
Follow-up challenges: 27.3% of levonorgestrel and 21.6% of copper IUD recipients lacked urine pregnancy tests, relying on self-reported surveys or health records.
Single-center design: Potential for site-specific biases.
Short-term outcomes: Only assessed pregnancy at 1 month; long-term EC efficacy or IUD continuation rates were not evaluated.
Low event rate: Only one pregnancy occurred, reducing statistical power to detect differences.

Clinical Relevance

This study suggests that the levonorgestrel IUD is a viable alternative to copper IUDs for EC, offering comparable efficacy within the prespecified margin. Clinicians may consider levonorgestrel IUDs for patients preferring hormonal contraception, which also provides long-term benefits (e.g., reduced menstrual bleeding). However, copper IUDs remain the gold standard for EC due to their established 0.1–0.2% failure rate and hormone-free mechanism. The findings could expand EC options, particularly for individuals with contraindications to copper (e.g., metal allergies) or those seeking immediate transition to long-term hormonal contraception. Further research is needed to validate results in diverse populations and assess cost-effectiveness.

Note: This study evaluated IUDs as EC, not oral copper supplements. The copper T380A IUD releases copper ions locally, distinct from systemic copper supplementation.