What are the methods of emergency contraception?

Methods of Emergency Contraception

There are four primary methods of emergency contraception available: Copper IUD, Ulipristal acetate, Levonorgestrel, and Combined estrogen-progestin regimens, with the Copper IUD being the most effective option for preventing pregnancy after unprotected intercourse. 1, 2

1. Copper Intrauterine Device (Cu-IUD)

• Highest effectiveness of all emergency contraception methods (>99% effective)
• Can be inserted within 5 days of unprotected intercourse
• Can be inserted beyond 5 days if ovulation timing is known (up to 5 days after ovulation)
• Provides ongoing contraception if left in place
• No decrease in effectiveness over the 5-day window 1, 2

2. Oral Emergency Contraceptive Pills (ECPs)

A. Ulipristal Acetate (Ella)

• Single 30mg dose
• Effective up to 120 hours (5 days) after unprotected intercourse
• More effective than levonorgestrel between days 3-5
• More effective for overweight or obese women than levonorgestrel
• Should be taken as soon as possible for maximum effectiveness 1, 2, 3
• After use, wait 5 days before starting or resuming hormonal contraception 3

B. Levonorgestrel (Plan B)

• Single 1.5mg dose or two 0.75mg doses taken 12 hours apart
• Most effective when taken within 72 hours (3 days)
• Effectiveness decreases with time after intercourse
• May be less effective in women who are overweight or obese
• Available without prescription 1, 2

C. Combined Estrogen-Progestin Regimen

• Two doses of 100μg ethinyl estradiol plus 0.50mg levonorgestrel taken 12 hours apart
• Less effective than ulipristal acetate or levonorgestrel
• Higher incidence of side effects (particularly nausea and vomiting)
• Rarely used now due to availability of better options 1, 4

Effectiveness Comparison

1. Copper IUD: >99% effective
2. Ulipristal acetate: Prevents approximately 85% of expected pregnancies
3. Levonorgestrel: Prevents approximately 75-80% of expected pregnancies
4. Combined regimen: Prevents approximately 74% of expected pregnancies 1, 2, 4, 5

Important Clinical Considerations

• Timing: All methods should be initiated as soon as possible after unprotected intercourse
• Vomiting: If vomiting occurs within 3 hours of taking ECPs, the dose should be repeated 3
• Future contraception: After using emergency contraception, a reliable barrier method should be used until the next menstrual period 1, 3
• Menstrual changes: ECPs may cause changes in the timing of the next menstrual period 3
• STI protection: None of these methods protect against sexually transmitted infections 1, 3
• Repeated use: Emergency contraception should not replace regular contraception methods; repeated use within the same cycle is not recommended 3

Special Considerations

• Obesity: Ulipristal acetate may be more effective than levonorgestrel in women with higher BMI 1, 2
• Advance provision: The CDC supports advance provision of emergency contraceptive pills 1
• Drug interactions: Effectiveness of ECPs may be reduced with enzyme-inducing medications (e.g., rifampin, certain anticonvulsants, St. John's Wort) 2, 3

Emergency contraception should be discussed with all patients of reproductive age as part of routine contraceptive counseling, with emphasis on the superior effectiveness of the copper IUD and the time-sensitive nature of all emergency contraceptive methods.