Emergency Contraception
Core concept: Emergency contraception (EC) prevents pregnancy after unprotected intercourse or contraceptive failure; it does not terminate an established pregnancy.
Key clinical distinction: Time since intercourse, weight-related efficacy concerns, current medications, and timing of resuming hormones determine the best method.
Prescribing priority: Offer the most effective accessible intervention without delaying care for an unnecessary examination or routine testing (Vernon, 2026).
Options and comparative selection
The 2024 birth-control methods chart identifies the copper IUD as a highly effective emergency-contraception choice (Reproductive Health National Training Center, 2024). Under CDC 2024 selected practice recommendations, it may be placed within five days of the first act of unprotected intercourse. When the day of ovulation can be estimated, it may also be placed more than five days after intercourse provided insertion occurs no later than five days after ovulation; clinical eligibility and other exposures still require assessment. The device can remain for ongoing contraception. Ulipristal acetate 30 mg orally once is an oral choice through 120 hours and is generally more effective than levonorgestrel later in that window; levonorgestrel 1.5 mg orally once is best taken as soon as possible. These choices are not equally effective across days 1–5 (CDC, 2024, Emergency Contraception; Vernon, 2026).
Eligibility and drug interactions
Ask about the timing of exposure, additional unprotected intercourse, current contraception, pregnancy symptoms, body weight/BMI, and medications. Enzyme-inducing medications can lower oral EC effectiveness. Higher body weight may reduce efficacy of levonorgestrel EC, whereas a copper IUD is not subject to the same drug interaction or weight concerns. An existing pregnancy should be excluded when indicated before device placement, but testing immediately after very recent exposure cannot rule out pregnancy from that event (Vernon, 2026).
Restarting contraception
After levonorgestrel emergency contraception, regular hormonal contraception can generally begin or resume immediately, with method-specific backup (typically seven days). After ulipristal acetate, CDC ordinarily recommends waiting at least five days before starting or resuming hormonal contraception because progestin exposure may reduce ulipristal effectiveness. For a provider-administered method requiring a visit (such as DMPA, an implant, or an IUD), same-day initiation after ulipristal may be considered only after weighing the potential decrease in ulipristal effectiveness against the risk that the patient will not return for initiation. A nonhormonal method may be started immediately. Counsel abstinence or barrier use through the relevant interval after the method becomes effective, and obtain a pregnancy test if no withdrawal bleeding occurs within three weeks (CDC, 2024, Emergency Contraception; Vernon, 2026).
Counseling and follow-up
Explain that nausea, temporary cycle changes, and spotting may occur. EC offers no continuing protection for additional intercourse and no STI protection. Assess whether sexual assault services, STI testing, HIV postexposure prophylaxis, or trauma-informed support is necessary, without making EC contingent on those services. Arrange a reliable longer-term contraceptive plan when desired.
A practical time-based selection pathway
For exposure within five days, offer a copper IUD when eligible and accessible, particularly if an enzyme-inducing drug may reduce oral emergency-contraception effectiveness. In selected cases where ovulation can be estimated, CDC permits insertion beyond five days after intercourse if no later than five days after ovulation. Otherwise, compare ulipristal acetate 30 mg once (through 120 hours) with levonorgestrel 1.5 mg once (best as soon as possible), including body-weight and interaction considerations. Do not imply that all methods are equally effective across the five-day window (CDC, 2024, Emergency Contraception; Vernon, 2026).
Continuity of contraception and exposure counseling
Discuss how to obtain the chosen ongoing contraceptive method and what to do if intercourse occurs before that method becomes effective. Emergency contraception does not prevent sexually transmitted infections or treat HIV exposure; offer exposure-specific evaluation and time-sensitive prevention separately when indicated (Vernon, 2026).
After the immediate dose: repeated exposure and follow-up
Emergency contraceptive pills address exposure that has already occurred; they do not protect reliably against intercourse later in the cycle. Discuss ongoing contraception before the patient leaves. After ulipristal, generally delay hormonal contraception for five days because progestin could reduce ulipristal efficacy; use barrier contraception through the recommended interval after method initiation. After levonorgestrel emergency contraception, a routine hormonal method may generally be started immediately with method-specific backup. Clarify vomiting after administration, as early vomiting can require another dose, and provide a pregnancy-test plan if menses are delayed or unusual (Vernon, 2026).
When the preferred method is unavailable
At 96–120 hours after exposure, the copper IUD and ulipristal are generally more effective choices than delayed levonorgestrel. If a device is acceptable but cannot be placed promptly, discuss timely oral therapy rather than losing the treatment window. Higher body weight and enzyme-inducing medications can reduce effectiveness of some oral strategies; explain uncertainty and documented alternatives. A 52-mg LNG-IUD for emergency use should be distinguished from its approved ongoing contraceptive indication and from device-specific evidence (Vernon, 2026).
Clinical application
A patient presents 96 hours after unprotected intercourse, requests future long-acting contraception, and cannot obtain a same-day IUD appointment. Discuss rapid access for copper IUD placement as the most established device option, versus ulipristal 30 mg orally now if the device is unavailable within the window. If ulipristal is selected, postpone starting hormonal contraception five days and explain barrier use, repeated-sex precautions, and pregnancy testing. Record an actual follow-up plan rather than assuming oral EC provides ongoing protection (Vernon, 2026).
High-yield distinctions
Do not restart a progestin immediately after ulipristal. A negative urine pregnancy test four days after intercourse cannot exclude pregnancy from that exposure. EC is preventive, not abortifacient therapy.
Related YourDNP Resources
Pharmacology learning hub · Combined hormonal contraception · Progestin-only contraception and LARC · Nonhormonal contraception
Content last reviewed:
References
Centers for Disease Control and Prevention. (2024, November 19). Emergency contraception: U.S. selected practice recommendations. https://www.cdc.gov/contraception/hcp/usspr/emergency-contraception.html
Reproductive Health National Training Center. (2024). Birth control methods chart [Patient education chart].
Vernon, V. P. (2026). Contraception. In M. A. Chisholm-Burns, P. M. Malone, J. M. Kolesar, K. C. Lee, P. B. Bookstaver, & K. R. Matthias (Eds.), Pharmacotherapy principles & practice (7th ed., Chapter 49). McGraw Hill.