Do All IUDs Work for Emergency Contraception Within 5 Days?
No, only the copper IUD is established as effective emergency contraception when placed within 5 days of unprotected intercourse—levonorgestrel IUDs are not currently recommended for this purpose based on available evidence. 1
Copper IUD: The Proven Option
The copper T380A IUD is the only IUD type with established efficacy for emergency contraception:
The copper IUD can be inserted within 5 days of unprotected intercourse as emergency contraception, and when ovulation timing can be estimated, insertion can occur beyond 5 days as long as it's within 5 days after ovulation. 1
The copper IUD prevents over 95% of unwanted pregnancies when used within this timeframe, with one large prospective study showing 100% effectiveness (0 pregnancies in 1,963 women). 2, 3
The device is immediately effective upon insertion—no backup contraception is needed. 4, 5
The copper IUD provides the additional benefit of ongoing contraception for up to 10 years. 1, 5
Levonorgestrel IUD: Insufficient Evidence
Despite recent interest, the levonorgestrel IUD should not be routinely offered as emergency contraception:
A 2021 randomized trial showed the levonorgestrel 52-mg IUD was noninferior to copper IUD (1 pregnancy in 317 vs. 0 in 321 women), but this single study has significant limitations and does not establish the levonorgestrel IUD as a recommended emergency contraception method. 6
A 2024 critical review in Obstetrics & Gynecology concluded that available data do not support use of the levonorgestrel IUD for emergency contraception, citing concerns about mechanism of action and insufficient evidence. 7
No major guidelines (CDC, ACOG, AAP) currently recommend levonorgestrel IUDs for emergency contraception—only copper IUDs are endorsed. 1
Clinical Implementation
When offering emergency contraception IUD placement:
Screen for pregnancy (absolute contraindication) and active STIs (particularly gonorrhea/chlamydia, which represent relative contraindications due to PID risk). 1, 5
STI screening can be performed on the day of insertion with treatment afterward if needed, without requiring device removal. 1, 5
Counsel patients that the copper IUD is more effective than oral emergency contraception (levonorgestrel or ulipristal), particularly for women who are overweight or obese. 1
Nulliparous women and adolescents are appropriate candidates—past concerns about safety in this population have been disproven. 1, 5
Common Pitfall
Do not assume all IUDs work for emergency contraception simply because one type does. The mechanism of action differs: copper ions are toxic to sperm and prevent fertilization/implantation, while levonorgestrel primarily works through ovulation suppression, which may not be effective if ovulation has already occurred. 7 Until more robust evidence emerges, stick with the copper IUD for emergency contraception.